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Bulletin N o . 1203 September 1956 Job P e r f o r m a n c e and Age: A Study in Measurement IOWA STATE t e a c h e r s C O L L E 0C T 22135& l ib r a r y UNITED S T A T E S D EPA RTM EN T OF LABOR James P. Mitchell, Secretary BUREAU OF LABOR STATISTICS Ewan Clague, Commissioner G E | ] Reports on the Department of Labor’s Older Worker Program: J o b Perform ance and Age: A Study in Measurement Older Workers under C o ll e c t iv e B argain ing: P a r t I. Hiring, R e te n tio n , J o b Term ination Older Workers under C o ll e c t iv e Barg ain ing : P a r t I I . Health, In su ra n ce, and P e n s i o n P l a n s P e n s i o n C o s t s in R e la ti o n to the Hiring of Older Workers Older Worker Adjustment to L a b o r Market P r a c t i c e s : An A n a ly s i s o f E x p e r ie n c e in Se v e n Major L ab o r Markets C o u n se lin g and P la c e m e n t S e r v i c e s for Older Workers How to Conduct an E arning-O pportunities Forum in Your Community Bulletin N o . 1203 September 1956 Job Performance and Age: A S tu d y in M e a su re m e n t UN ITED S T A T E S D EP A R TM EN T OF James P. Mitchell, Secretary LABOR BUREAU OF LABOR STATISTICS Ewan Clague, Commissioner For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington 25, D.C. - Price 45 cents P re fa ce O ne o f t h e m o s t p r e s s in g p r o b le m s c o n f r o n t in g t h i s N a t io n c o n c e r n s t h e d i f f i c u l t i e s o f t h e o l d e r w o r k e r i n s e c u r in g a n d r e t a i n i n g e m p lo y m e n t* T h e U* S . D e p a r tm e n t o f L a b o r , a w a r e o f t h e s e d i f f i c u l t i e s , h a s u n d e r ta k e n a b r o a d p r o g r a m t o e x a m in e t h e s e p r o b le m s , a n d , i f p o s s i b l e , t o f i n d m e a n s f o r o y e r c o m in g t h e m . A s p a r t o f t h i s p r o g r a m , t h e p r e s e n t s t u d y e x a m in e s t h e p r o b le m s o f m e a s u r in g t h e r e l a t i o n s h i p s , i f a n y , b e tw e e n a g e a n d w o r k p e r fo r m a n c e , N m e r o u s s t u d i e s h a v e r e c o r d e d th e a t t i t u d e s o f e m p lo y e r s o n t h i s s u b j e c t , a n d h a v e r e v e a le d a r a t h e r w id e s p r e a d s e t o f u n fa v o r a b le b e l i e f s c o n c e r n in g th e w ork p e r fo rm a n ce o f o ld e r w o rk ers* I t i s a f a i r p r e s u m p tio n t h a t t h e r e i s so m e r e l a t i o n s h i p b e tw e e n t h e s e a t t i t u d e s a n d t h e p r o b le m s m e n tio n e d a b o v e * I t i s im p o r ta n t, t h e r e f o r e , to e x a m in e , th r o u g h o b j e c t i v e m e a s u r e m e n ts , t h e q u e s t io n o f h o w a g e a c t u a l l y a f f e c t s jo b p e r fo r m a n c e * A b a s ic f a c t o r in e s t a b lis h in g th e n e e d f o r t h i s s tu d y w a s th e a lm o s t t o t a l la c k o f p a s t su r v e y s, o f an y e x te n s iv e so o p e , in t h is f ie ld * S in c e i t i s e x tr e m e ly un com m on , i n p r o d u c tiv e e n t e r p r is e s , to f i n d la r g e g r o u p s o f w o r k e r s p e r fo r m in g t h e sa m e t a s k , p r e v io u s s t u d i e s o f a g e a n d w o r k p e r fo r m a n c e h a v e m ade l i t t l e u s e o f o n - t h e - j o b p e r fo rm a n ce r e c o r d s b e tw e e n a g e a n d jo b p e r fo r m a n c e * A B ureau v e lo p m a c tu a l lth o u g h n o t m in im iz in g t h e d i f f i c u l t i e s o f c o n d u c tin g su c h a s t u d y , t h e o f L a b o r S t a t i s t i c s t h o u g h t t h a t i t w o u ld b e p o s s i b l e , t h r o u g h t h e d e e n t o f s u it a b le t e c h n iq u e s , to o v erco m e m any o f th e o b s t a c le s to u s in g p e r fo r m a n c e d a ta d e r iv e d fr o m p la n t r e c o r d s * The area o f p r o b le m s a lth o u g h v a ila b le o u t in a fa c e d in B u rea u a ls o r e c o g n iz e d th a t th e s e d i f f i c u l t i e s w ere n o t p u r e ly in th e s t a t i s t i c a l m a n ip u la tio n , b u t in v o lv e d a n in t e r p la y o f s t a t i s t i c a l w it h p r o b le m s o f d a t a c o ll e c t i o n * I t w a s c o n c lu d e d , t h e r e f o r e , t h a t t h e n e c e s s a r y s t a t i s t i c a l t o o l s w e r e u n d o u b te d ly a t h a n d i n th e a l i t e r a t u r e , th e a c t u a l a p p lic a t io n o f t h e s e t o o l s c o u ld b e s t b e w o r k e d p i l o t s t u d y , i n w h ic h a l l o f t h e im p o r t a n t o b s t a c l e s w o u ld h a v e t o b e a p r a c tic a l w ay* In th e a c t u a l c o n d u c t o f th e s tu d y , i t w as fo u n d th a t c e r t a in te c h n iq u e s w h ic h s e e m e d i n i t i a l l y t o m e e t t h e n e e d s o f t h i s p r o g r a m w e r e , i n p r a c t i c e , u n s u ita b le * I n t h e s e c a s e s , a l t e r n a t i v e m e th o d s w e r e d e v e lo p e d a n d t e s t e d * F o r e x a m p le , i t w a s b e lie v e d t h a t c l a s s i f i c a t i o n o f w o r k e r s in t o 5 - y e a r a g e g r o u p s w o u ld b e a n a p p r o p r ia t e m e a n s o f i d e n t i f y i n g t h e a g e f a c t o r . In a t te m p tin g to a p p ly t h i s p r o c e d u r e , h o w e v e r , i t w a s d is c o v e r e d t h a t t h e n u m b er o f o b s e r v a t io n s i n e a c h g r o u p w a s t o o s m a ll t o p e r m it m e a n in g fu l c o m p a r is o n s , an d 1 0 -y e a r c l a s s i f ic a t i o n s w ere s u b s titu te d * In a n o th e r in s ta n c e , i t w as a ssu m e d t h a t s k i l l l e v e l s f o r e a c h o c c u p a t io n c o u ld b e d e te r m in e d th r o u g h t h e u s e o f th e D ic t io n a r y o f O c c u p a tio n a l T it le s * T h is w a s a ls o fo u n d to b e u n w o r k a b le a n d a d i f f e r e n t m e th o d o f s k i l l - l e v e l c l a s s i f i c a t i o n h a d t o b e u s e d * - ill - S u ch d i f f i c u l t i e s a r e in h e r e n t in th e s u b je c t m a tte r o f t h i s s u r r e y . C om pany r e c o r d s sh ow l i t t l e o r n o u n ifo r m ity , a n d a r e n o t d e s ig n e d to y i e l d t h e t y p e o f in f o r m a t io n n e e d e d i n a p r o g r a m o f t h i s s o r t . Y e t so m e s ta n d a r d iz a t io n o f d a t a - c o lle c t in g p r o c e d u r e s w a s o b r io u s ly n e e d e d in o r d e r to p r o v id e s t a t i s t i c s t h a t w o u ld b e c o m p a r a b le a m o n g t h e v a r io u s p l a n t s . T h is s t a n d a r d i z a t i o n r e q u ir e d a d e t a i l e d e x a m in a tio n o f th e r e c o r d s a c t u a l l y m a in t a in e d i n i n d u s t r i a l p l a n t s , f o llo w e d t y a n a n a l y s is o f h ow t h e s e r e c o r d s m ig h t b e u s e d to d e r iv e c o h e r e n t m e a su r e s o f jo b p e r fo r m a n c e . T he a n a ly s is h a d to m ake p r o v is io n n o t o n ly f o r v a r ia t io n s in r e c o r d k e e p in g , b u t a ls o f o r d if f e r e n c e s in t h e b a s i c d e f i n i t i o n s e m p lo y e d b y v a r io u s c o m p a n ie s . F o r e x a m p le , i t w a s fo u n d t h a t th e d is t in c t io n b e tw e e n te r m in a tio n s a n d le a v e s o f a b se n c e w a s n o t c l e a r c u t , a n d v a r ie d fr o m p la n t t o p l a n t . S im ila r p r o b le m s o f i n t e r p r e t a t io n a r o se in ea ch o f th e o th e r a r e a s . I t w a s a n t i c i p a t e d t h a t t h e r e w o u ld b e a e r r o r , a n d t h a t t h i s w o u ld t e n d t o r e d u c e t h e o u t o f a s t u d y w h ic h h a d t o b e c o m p le t e d i n a b e lie v e d , n e v e r th e le s s , th a t su ch a stu d y c o u d e v e lo p in g a n d t e s t i n g v a r io u s n ew a p p r o a c h e s la t io n s h ip s b e tw e e n a g e a n d w ork p e r fo r m a n c e . c e r ta in am ount o f t r i a l an d q u a n t i t y o f d a t a t h a t w o u ld co m e g iv e n p e r io d o f tim e . I t w a s ld m e e t a n im p o r ta n t n e e d b y to th e in v e s tig a tio n o f r e B y i t s n a tu r e , t h is program w as n o t e x p e c te d to p ro d u ce a n y e x te n s iv e fin d in g s w ith r e s p e c t to th e s e r e la t io n s h ip s . N e v e r th e le s s , m any o f th e p r o c e d u r e s u s e d w e r e s i m i l a r t o t h o s e w h ic h m ig h t b e r e q u ir e d i n a f u l l - s c a l e su r v e y , and th e r e s u lts o f th e se p ro ced u res a r e , th e r e fo r e , p r e se n te d a s s ta t i s t i c a l f in d in g s in th e b o d y o f th e r e p o r t . T h e se s t a t i s t i c s a p p ly o n ly to th e p a r tic u la r p la n ts th a t w ere c o v er ed in t h is su r v e y , h o w ev er, an d a r e n o t i n a n y w a y in t e n d e d t o r e p r e s e n t c o n d it io n s t h a t m ig h t b e fo u n d t o e x i s t i f an e n t ir e in d u s tr y h ad b e e n su r v e y e d . T h is s t u t y w a s c o n d u c te d i n th e D iv is io n o f P r o d u c t iv it y a n d T e c h n o lo g ic a l D e v e lo p m e n ts u n d e r t h e d i r e c t i o n o f J e r o m e A . H a r k , w h o p r e p a r e d t h e r e p o r t w i t h W o lfr a m L l e p e a n d B e r n a r d R e i n , a s s i s t e d b y R o b e r t E . M a la k o f f a n d S ta n le y M ille r . T h e s t a t i s t i c a l fo r m u la s w e r e d e r iv e d w ith th e a s s is t a n c e o f M o rto n R a f f o f t h e B u r e a u 's O f f ic e o f S t a t i s t i c a l S ta n d a r d s . T h e B u r e a u w is h e s t o e x p r e s s i t s a p p r e c ia t io n t o t h o s e f ir m s w h o se w h o le h e a r te d c o o p e r a tio n m ade t h is w o rk p o s s ib le . T h ey g e n e r o u s ly m ade t h e ir r e c o r d s a v a ila b le to th e B u r e a u 's r e p r e s e n t a t iv e s a n d o f f e r e d m any h e lp f u l s u g g e s tio n s . - iv - CONTENTS Page P r e f a c e ....................................................................................................................................................................................................................... i S u n m a r y .............................................................................................................. • . ............................................................................................. 1 P u r p o s e a n d S c o p e o f S u r v e y .................................................................................................... I n d ic a t o r s o f W ork P e r fo r m a n c e * D e f in it io n a n d M eth o d s o f M e a su r e m e n t. 8 O u t p u t p e r M a n - H o u r ........................................................................................................................................................................... 8 L i m i t a t i o n s o f C o m p a r in g E m p lo y e d P ie c e w o r k e r s ..................................... . . . . . 9 O b s e r v a t i o n P e r i o d .............................................................................................................................................................. 10 G r o u p s f o r D i r e c t C o m p a r is o n ................................................................................................................................... 1 0 A t t e n d a n c e ...................................................................................................................................................................................................................1 1 O b s e r v a t i o n P e r i o d .................................................................................................................................. G r o u p s f o r D i r e c t C o m p a r is o n ....................................................................................................................... 12 I n d u s t r i a l I n j u r i e s ..................................... * .................................................................................................... 12 N o n d i s a b l i n g I n j u r i e s ....................................................................................................................... D i s a b l i n g I n j u r i e s ...............................................................................................................................................................................1 3 O b s e r v a t i o n P e r i o d ............................................................................................................................... G r o u p s f o r D i r e c t C o m p a r is o n ...........................................................................................................................................l U S e p a r a t i o n s .................................................................................................................................................................................................................. I l l G r o u p s f o r D i r e c t C o m p a r i s o n .............................................................................................. I n d u s tr y a n d P la n t S e l e c t i o n ............................................................................................................................................ 16 D a t a C o l l e c t i o n P r o c e d u r e s .................................................................................................. S t a t i s t i c a l M e t h o d s .............................................................................. 20 A g e G r o u p s ......................................................................................................* ................................................. ...........................................2 0 O u t p u t P e r M a n - H o u r .................................................................................................................................................................. 20 O c c u p a t i o n a l G r o u p s ................................................................................................................................................................... 21 P r o c e d u r e f o r C o m b in in g I n d e x e s o f S p e c i f i c O c c u p a t io n s . . . . . . 21 C o m b i n i n g I n d e x e s o f O c c u p a t i o n a l G r o u p s ................................................................................ 22 I n d iv id u a l V a r ia tio n . . . . . . ..................................... . . . . . . . . . . . 22 A t t e n d a n c e ...................................................................................................................................................................................................................2 3 I n d u s tr ia l I n ju r ie s . . . . . . ................................................................................................................................... 2 U S e p a r a t i o n s ................................................................ 2 li F in d in g s in t h e P la n t s S u r v e y e d . . . . . ........................................................................................................... 2 5 O u t p u t P e r M a n - H o u r ............................................................................................................................................................... ....... . 25 M e n a n d W o m e n ............................................................................................. 25 H i g h e r a n d L o w e r P a i d O c c u p a t i o n s .............................................................................................................................2 8 M a c h in e a n d H a n d O c c u p a t io n s ............................................................................................ 31 I n i t i a l O c c u p a t i o n a l G r o u p s ............................................................................................................ A tte n d a n c e ................................................................................................................................................................................................. 36 I n d u s t r i a l I n j u r i e s ................................................................................................................................................. S e p a r a tio n s .................................................... . . . . . . . ............................... 3 9 TABLES 1. 2. In d ex es o f e s ta b lis h m In d ex es o f e s ta b lis h m o u tp u t p e n ts, b y o u tp u t p e n ts, b y e r m a n -h o u r se x and a g e e r m a n -h o u r sex and age f o r p ie c e w o r k e r s in fo u r fo o tw group ................................................................... . . f o r p ie c e w o r k e r s in fo u r c lo t h group .................................................................. . . - v - ear . . . in g . . . 26 26 12 Il 31 39 CONTENTS— C o n tin u e d Page TABLES— C o n tin u e d 3* 1|. 5* 6. 7* 8. 9. 10. 11. 12. . 13* Indexes of output per nan-hour for nen pieceworkers in higher and lower paid occupations in four footwear establishments, by age g r o u p ........................ 29 Indexes of output per man-hour for women pieceworkers in higher and lower paid occupations in four footwear establishments, by age g r o u p ............................... 29 Indexes of output per man-hour for men pieceworkers in higher and lower paid occupations in four clothing establishments, b y age g r o u p ............................................. 30 Indexes of output per man-hour for women pieceworkers in higher and lower paid occupations in four clothing establishments, b y age group ............................................................. 30 Indexes of output per man-hour of men pieceworkers performing machine and hand operations in four footwear establishments, by age g r o u p ................................. 32 Indexes of output per man-hour of women pieceworkers performing machine and hand operations in four footwear establishments, b y age g r o u p ............................................................. 32 Indexes of output per man-hour of men pieceworkers performing machine and hand operations in four clothing establishments, by age g r o u p ............................................................. 33 Indexes of output per man-hour of women pieceworkers performing machine and hand operations in four clothing establishments, b y age g r o u p ............................................................. 33 Indexes of output per man-hour of pieceworkers in four footwear establishments, by sex, age group, and type of occupation . . . . . 3U Indexes of output per man-hour of pieceworkers in four clothing establishments, by sex, age group, and type of occupation . . . . . 35 Indexes of attendance of pieceworkers in four footwear establishments, by sex and age group . . • • • • . . . • 37 Indexes of attendance of pieceworkers in four clothing establishments, b y sex and age group ..... .............. 37 Indexes of attendance for pieceworkers in higher and lower paid occupations in four footwear establishments, by sex and age group • 38 Indexes of attendance for pieceworkers in higher and lower paid occupations in four clothing establishments, by sex and age group • 38 Industrial injuries of pieceworkers, in selected shoe plant A by sex, occupation and age group, during 1 -year period ending December 31, 1955 ........ ................................... .. 1*0 Industrial injuries of pieceworkers, in selected clothing plant B b y sex, occupation and age group, during 2 -year period ending December 31, 1 9 5 5 .................................................. 1»1 111 * 15. 16. 17. 18. - v i - CONTENTS— C o n tin u e d TABLES— Continued. 19* 20* 21. Industrial injuries of pieceworkers, in selected clothing plant C by sex, occupation and age group, during 2 -year period ending December 31, 1 9 5 5 .................................................. U2 Indexes of separation rates of pieceworkers in two footwear plants b y sex, length of service, and age group . . . . . . . . . . I4I1 Indexes of separation rates of pieceworkers in two men's clothing plants by sex, length of service, and age group ................... U 5 APPENDIX 1. 2. 3. U. Further Notes on Statistical M e t h o d s ................................U6 Definition of U n i v e r s e ...................... U6 Occupational Classification . . . . . . . . . . . ............... U7 Transforming Absolute Scores Into Indexes ............... .. U9 Combining Occupation Indexes . . . . . . . . . . . . . ........ U9 Measures of Dispersion 50 Statistical Significance Testing . . . . . . . . ........ . . . £0 Derivation of F o r m u l a s ............ 52 Weights for Combining Indexes for Specific Occupations ........ 52 Variance of an Age Group Index for an Occupation Group . . . . . 5U Weights for Combining Indexes to Base A with Indexes to Base B • 5U Variance of the Combined Index .................................. 56 Coefficient of Variation for an Occupational Group . . . . . . . 58 Combining Occupational Group Indexes .............................. 59 Questionnaire and Worksheets . ........ . . . . . . . . . . . . . 61 6U Instructions for Questionnaire and Worksheets • ........ . . . . . - v ii - Job Performance and Age: A Study in Measurement The present stucfcr of job performance and &ge was undertaken by- the Bureau of Labor Statistics as part of a general program of the Department of Labor to investigate the employment problems of older workers, and to find ways to meet these problems. This study, exploratory in nature, was designed to develop objective measures which would be useful for comparing the performance of production wo iters in different age groups. It was intended only as a pilot investi gation to guide future and more extensive work. Four Indicators of work performance, ostensibly straightforward but in fact quite complex, were carefully defined. It was found that at least three of these can be used to relate age to job performance--output per man-hour, attendance, and separation rates. Research was confined to 8 manufacturing establishments in 2 industries— footwear and men* s clothing. Output data were obtained for 2,217 production workers— 933 in the footwear industry and 1,281* in the clothing industry. Attendance data were collected for 1*,009 production workers of which 1,7 5 8 were in the footwear plants and 2,251 were in the clothing plants. Data on industrial injuries were collected for 2 ,6 3 7 workers, of whom 729 were in footwear plants and 1,908 in clothing plants. Records of separations (quits, layoffs, and discharges) were kept in detail at only 1* of these plants; they provided figures for 2 ,731* workers over the period of a year or more. Data obtained in the course of this pilot survey, while describing the experience of the plants visited, were not expected to (nor do they) furnish definitive results of these industries. The main emphasis was on the devel opment of techniques suitable to a full-scale investigation. Findings in the Plants Surveyed It was found possible to draw conclusions of only a limited nature with respect to the relationships between age and work performance. In the case of output p o t man-hour, the data showed, in general, a stable average performance level through the age of 5U, with some falling off occurring in the av erage for the 55-61* year group. Although the declines were, in most cases, statistically significant, the indexes of output for this age group were within approximately 10 percent of those for the age groups with peak production. Variations in the output of persons In the same age group were very large— in fact, they were greater than the differences in average output among age groups. This means, for example, that many workers aged 55-61* had output rates which were actually higher than the average rate in the age group with peak production. Conversely, many younger workers had output lower than the - 1 - average output of older workers. Insofar as practical implications are concerned, these data emphasize the fact that an employer in considering an applicant for employment should evaluate the potentialities of the individual rather than immediately drawing conclusicns from his chronological age* The age-output curves ty industry, sex, type of operation (hand or ma chine) and earnings levels followed the same general patterns in each industry both in regard to averages for age groups and variations of the output of individuals within the same age group. With respect to attendance, only small differences were found among age groups* In the shoe plants, indexes of attendance for the six age groups varied by only 3 percent, and in the clothing plants by only 7 percent* With regard to industrial Injuries, the stu^y did not provide data which could be used to make comparisons between age groups* This was due partly to the lack of uniformity in company injury records, and also to the fact that a survey with wider coverage would be needed to produce meaningful results* Marty age groups showed no Injuries during the years studied* Information on separations was collected, but the adequacy of this in formation varied among the several plants surveyed, and it was found possible to present findings for only four of these plants* The data showed, in gen eral, a high rate of quits and discharges for cause for workers under 2$ years old* In two plants there were extremely low rates for the age group 1(5 to 6 U$ in the others no pattern was found* After 65 retirement influenced the results markedly* In view of the relatively small coverage of the study, it is not possible to identify any significant differences in the age-separations patterns shown by the various groups. In a larger scale survey, however, it would probably be important to retain the categories used here, in which distinctions are made according to sex, industry, and length of service* Measures of Job Performance Pour indicators of work performance— output per man-hour, attendance, industrial injuries, and separations— were selected for comparing age groups because they afforded objective measures, and data for them were thought to be directly available from plant records* Output per man-hour was measured by comparing the average hourly piecerate earnings of individuals working at the same operation* Many plants which use a piecework system maintain reoords on Individual average hourly earnings* No means were found to measure the output of timeworkers, nor were data available on quality of work produced by individual employees* Attendance was defined as the ratio of days worked to days scheduled* Although this is a relatively straightforward measure, the lack of uniform and complete plant records created difficulties in deriving attendance rates* - 2 - I n d u s t r i a l i n j u r i e s . S e r io u s p r o b le m s w e r e e n c o u n te r e d i n m e a s u r in g i n d u s t r i a l i n j u r i e s * D i f f e r e n c e s i n r e c o r d k e e p in g p r a c t i c e s o f p l a n t s , p a r t i c u l a r l y w i t h r e s p e c t t o n c n d is a b l l n g i n j u r i e s a n d t h e f r e q u e n t l a c k o f d a t a o n t o t a l h o u r s w o rk ed b y i n d i v i d u a l s f o r a s l o n g a s a y e a r w e r e th e m o st s e r io u s * M o r e o v e r , t h e e x t r e m e ly lo w i n c i d e n c e o f i n j u r i e s w o u ld h a v e n e c e s s i t a t e d t h e c o l l e c t i o n o f d a ta f o r a l o n g p e r io d o f tim e * T h is w a s fo u n d t o b e p r o h i b i t i v e w i t h i n t h e tim e a n d fu n d s a v a i l a b l e f o r t h i s s t u d y , a n d t h e r e f o r e t h e d a t a p r o v id e n o i n j u r y r a t e s b y &g® f o r t h e p l a n t s c o v e r e d * S e p a r a t i o n s * Some p l a n t s d id n o t m a in ta in d e t a i l e d r e c o r d s o f q u i t s , l a y o f f s , a n d d is c h a r g e s * P r o b le m s w e r e a l s o e n c o u n te r e d i n d i s t i n g u i s h i n g s e p a r a t i o n s fr o m e x te n d e d a b s e n c e s * T he r e c o r d s a v a i l a b l e w e r e s o v a r i e d i n d e t a i l t h a t i t w a s fo u n d p o s s i b l e t o p r e s e n t i l l u s t r a t i v e f i n d i n g s f o r o n l y fo u r o f th e p la n ts * S t a t i s t i c a l M eth o d s S in c e t h e d a t a c o l l e c t e d i n t h e p l a n t s p e r t a in e d o n l y t o i n d i v i d u a l w o r k e r s , i t w a s n e c e s s a r y t o a p p ly som e p r o c e s s w h ic h w o u ld l e a d t o f i n d i n g s o f a m ore g e n e r a l n a tu r e * T h is w as d o n e i n t h e f o l l o w i n g w ay* E ach w o r k e r w a s c l a s s i f i e d b y a g e , i n t o o n e o f s i x g r o u p s * T he w o r k e r s w e r e th e n f u r t h e r c l a s s i f i e d i n t o g r o u p s b y c h a r a c t e r i s t i c s w h ic h m ig h t b e r e l a t e d t o w ork p e r fo r m a n c e , s u c h a s s e x , p la n t w h e r e e m p lo y e d , o c c u p a t io n , a n d l e n g t h o f e x p e r ie n c e * T he p a r t i c u l a r c h a r a c t e r i s t i c s e m p lo y e d a s c r i t e r i a v a r ie d w ith t h e m e a su r e s o u g h t; th e p u r p o s e , i n e a c h i n s t a n c e , w a s t o g ro u p t o g e t h e r t h e w o r k e r s who c o u ld b e c o n s id e r e d h o m o g en eo u s w it h r e s p e c t t o t h e n o n -a g e f a c t o r s a f f e c t i n g t h e m ea su re u n d e r c o n s id e r a t io n * D i r e c t c o m p a r is o n s w e r e m ade am ong i n d i v i d u a l s w i t h i n t h e s e g r o u p s* F o r o u tp u t p e r m a n -h o u r e a c h o c c u p a t io n w a s t r e a t e d s e p a r a t e l y , s i n c e i t w a s b e l i e v e d t h a t t h e n a tu r e o f t h e s p e c i f i c o c c u p a t io n h a s a b e a r in g o n o u tp u t* F o r a t t e n d a n c e , on t h e o t h e r h a n d , i t w a s f e l t t h a t t h e s p e c i f i c o c c u p a t io n o f a w o r k e r w o u ld h a v e l i t t l e i n f l u e n c e on h i s a t t e n d a n c e r a t e b u t t h a t th e g e n e r a l e a r n in g s l e v e l o f h i s j o b m ig h t a f f e c t i t * I n a n a l y z in g d a ta f o r w o r k e r s w i t h i n o n e o f t h e s e h o m o g en eo u s g r o u p in g s , a n y d i f f e r e n c e i n p e r fo r m a n c e am cng a g e g r o u p s c a n b e m ore c l e a r l y r e l a t e d t o a g e * T h e s e d i f f e r e n c e s w e r e m ea su re d b y c a l c u l a t i n g in d e x e s f o r e a c h a g e g r o u p a v e r a g e , w ith th e 35-UU y e a r g ro u p a s th e b a s e * T h is w a s d o n e s e p a r a t e l y f o r o u t p u t p e r m a n -h o u r , a t t e n d a n c e , a n d s e p a r a t i o n s . T h rou gh th e u s e o f I n d e x e s a n d th e c l a s s i f i c a t i o n s y s t e m , th e i n f l u e n c e o f n o n -a g e f a c t o r s w a s s u b s t a n t i a l l y e l i m i n a t e d , s i n c e e a c h w o r k e r w a s b e i n g com p ared o n l y w i t h o t h e r w o r k e r s who h a d t h e s e f a c t o r s i n common w it h him * T he in d e x e s c o u ld th e n b e o o m b in ed t o o b t a in l a r g e r g r o u p in g s b y a v e r a g in g t h e I n d e x e s , w it h e a c h co m p o n en t o f th e a v e r a g e b e in g a s s ig n e d a w e ig h t w h ich d e p e n d e d on th e num ber o f i n d i v i d u a l s r e p r e s e n t e d . * * * - 3 - • T h e p r e s e n t stu cjy h a s c l a r i f i e d a n d s o lv e d s o n s o f t h e m o st im p o r ta n t p r o b le m s t h a t m u st b e f a c e d i n o b j e c t i v e l y m e a s u r in g th e r e l a t i o n s h i p o f a g e t o w o rk p e r fo r m a n c e . I n fo r m a tio n a b o u t t h e a v a i l a b i l i t y a n d a d e q u a c y o f p l a n t r e c o r d s w a s o b t a i n e d a n d p r o c e d u r e s w e r e d e v e lo p e d f o r o b t a i n i n g d a ta * A m ean s w a s fo u n d f o r c o m p a r in g t h e p e r fo r m a n c e o f w o r k e r s i n d i f f e r e n t o c c u p a tio n s . M eth o d s w e r e d e v i s e d f o r a p p r o p r i a t e l y c o m b in in g d a ta i n t o l a r g e r a g g r e g a t i o n s i n o r d e r t h a t m ore g e n e r a l an d m ore r e l i a b l e c o n c lu s io n s c o u ld b e o b ta in e d . T h e r e s u l t s show n i n t h i s r e p o r t a l t h o u g i n o t f u r n i s h i n g c o n c lu s iv e a n s w e r s t o t h e q u e s t i o n w it h w h ic h i t d e a l s , r e p r e s e n t s an im p o r ta n t p r e l i m i n a r y s t e p to w a r d f u r t h e r w ork i n t h i s a r e a . - k - Purpose and Scope of Survey How age affects work performance is a subject on which little factual infomation is available* nevertheless, the belief that work performance declines as age increases is widespread, and constitutes one of the most important barriers to the employment of older workers* Studies of employers' attitudes toward older workers have consistently shown that this belief is one of the reasons most frequently cited for failing to hire older workers* The Temple University Bureau of Economics and Business Research conducted a study In conjunction with the Pennsylvania Bureau of Bnployment Security, the results of which were reported in 1953 at the Second Conference on the Problems of Making a Living While Growing Old. In response to the question *Vhat factors in your view tend to limit the feasibility of hiring older workers?" the survey found that companies offered a variety of reason a for restricting the hiring of older workers, but the most important of the reasons given were "rate and quality of production." l/ Similarly, in the Employment Security Review of December 1950, it was reported that "several surveys conducted by the Bureau of Employment Security in cooperation with affiliated State agencies reveal that the reasons most frequently given for not hiring older workers ares (1) Fear the hiring of older workers would increase workmen* s compensation and insurance costs, (2 ) less productive and unable to meet physical requirements, (3 ) greater injury rates, (U) difficulty in retraining, and (5 ) promotion from within policies* 2/ 3 / Consequently, it is believed that data on job performance b y age can be used to test, within selected occupational areas, whether these notions are in fact valid* The results obtained can provide additional information for employers and may indicate in what occupational areas there are real problems* 1/ Millard E. Gladfelter, provost and vice president of Temple University,~Age and Employability in Pennsylvania (in Proceedings of the Second Conference on the Problem of Making a Living QCile Growing Old) * Commonwealth of Pennsylvania and Temple University, 1953 (p* 27 and table XII, p* 398)* 2 / William Mirengoff, Older Worker Employment - Benefit or Burden, Deployment Security Review, December 1950 (p* 9)* 3/ Similar findings regarding the importance of employers' attitudes on work performance as a barrier to the employment of older workers can be found In other studies* See, e.g., The Employer and the Older Worker by the Personnel Club of Mew York (In Making the Years Count), New York State Joint Legislative Committee on Problems of Aging, Legislative Document 32, 1955 (p. 88) $ also Personnel Policy and Older Workers— an Overview b y Lazare Teper, Director of Research, International Ladieaf Garment Worker^ Union (in Age Barriers to Employment, Proceedings of the Third Joint Conference on The Problem of Making a Living While Growing Old, 195U (p. U5) $ and New York State Legislature, No Time to Grow Old* New York State Legislature Document 12 of 1951 (p* 115). - 5 - B e f o r e t h i s s t u d y o f o n - t h e - j o b p e r fo r m a n c e d a t a f o r p r o d u c t io n w o r k e r s i n m a n u fa c tu r in g e s t a b l i s h m e n t s w a s u n d e r ta k e n * i t w a s r e c o g n iz e d t h a t m any m e t h o d o lo g ic a l p r o b le m s e x i s t e d an d t h e t e c h n iq u e s u s e d i n o t h e r s t u d i e s o f t h e p e r fo r m a n c e o f w o r k e r s d id n o t a p p ly d i r e c t l y t o t h e s p e c i a l n e e d s o f t h e cu rren t in v e s tig a tio n . T he m e t h o d o lo g ic a l p r o b le m s w h ic h w e r e r e c o g n iz e d a f f e c t e d e a c h o f t h e t h r e e im p o r ta n t a r e a s i n t h i s r e s e a r c h — s e l e c t i o n o f a p p r o p r ia t e p e r fo r m a n c e i n d i c a t o r s * t e c h n i q u e s o f d a t a c o l l e c t i o n * a n d s t a t i s t i c a l m e th o d s* I t w a s d e te r m in e d * t h e r e f o r e * th e p r e s e n t s t u d y w o u ld a im a t p r o v id in g t h e t o o l s n e c e s s a r y f o r f u t u r e w ork i n t h i s f i e l d * r a t h e r th a n a c c u m u la tin g e x t e n s i v e d a t a th r o u g h l e s s r e f i n e d m e th o d s . C o n s e q u e n tly * t h e c u r r e n t w ork w a s d e s ig n e d a s a p i l o t i n v e s t i g a t i o n o f r e l a t i o n s h i p s w h ic h m ig h t e x i s t b e tw e e n w o rk p e r fo r m a n c e a n d a g e * b u t d a t a o b t a in e d w e r e n o t e x p e c t e d t o f u r n i s h d e f i n i t i v e r e s u lt s f o r t e s t in g g e n e r a l n o tio n s a b o u t o ld e r and y o u n ger w o rk ers. M ore s p e c i f i c a l l y * t h e o b j e c t i v e s o f t h e c u r r e n t s t u d y w e r e t o j ( 1 ) D e te r m in e w h ic h o f t h e a v a i l a b l e i n d i c a t o r s c o u ld b e u t i l i s e d t o co m p a re t h e j o b p e r fo r m a n c e o f w o r k e r s o f d i f f e r e n t a g e s * ( 2 ) e s t a b l i s h a n d r e f i n e p r o c e d u r e s f o r c o l l e c t i n g d a t a o n t h e s e i n d ic a t o r s * ( 3 ) d e v i s e s t a t i s t i c a l t e c h n iq u e s f o r d e v e lo p in g v a l i d m e a s u r e s o f j o b p e r fo r m a n c e * a n d (U ) i f p o s s ib le * p r e s o r t fin d in g s o f th e c u r r e n t s tu d y on a n y o b se r v e d r e la t io n s h ip s b e tw e e n a g e a n d w ork p e r fo r m a n c e f o r t h e l i m i t e d num ber o f p l a n t s s t u d i e d . How t o O b ta in P e r fo r m a n c e D a ta I n f o r m a t io n o n t h e c o m p a r a tiv e p e r fo r m a n c e o f i n d i v i d u a l s o f d i f f e r e n t a g e s c a n b e o b t a in e d i n v a r i o u s w a y s . P a s t s t u d i e s o n w ork p e r fo r m a n c e a n d a g e a r e o f t h r e e g e n e r a l t y p e s — l a b o r a t o r y e x p e r im e n t a l s t u d i e s * o p in io n s u r v e y s b a s e d o n s u p e r v i s o r s ' r a t in g s * a n d i n v e s t i g a t i o n o f o n - t h e - j o b p e r fo r m a n c e d e r iv e d fro m com pan y r e c o r d s * T he l a b o r a t o r y s t u d i e s g e n e r a l l y d e a l w ith s p e c i f i c p h y s i c a l o r p s y c h o l o g i c a l c h a r a c t e r i s t i c s * su c h a s m a n u a l d e x t e r i t y * s t r e n g t h o f g r ip * a n d l e a r n i n g a b i l i t y * h/ T h e se s t u d i e s a r e v a lu a b l e f o r p r o v id in g i n s i g h t i n t o t h e m e c h a n ic s o f t h e a g in g p r o c e s s . H ow ever* t h e y a r e o f l i m i t e d a p p l i c a b i l i t y t o a c t u a l j o b p e r fo r m a n c e * s i n c e t h e y d o n o t t a k e i n t o a c c o u n t t h e c o m p le x i n t e r a c t i o n s o f in n u m e r a b le p h y s i c a l a n d p s y c h o l o g i c a l c h a r a c t e r i s t i c s * n o r U / S e e * e . g . * A . J . W e lf o r d , S k i l l a n d Age* a n E x p e r im e n ta l A p p roach * p u b lis h e d f o r t h e T r u s t e e s o f th e H u f f i e l d F o u n d a tio n b y O x fo r d U n i v e r s i t y P r e s s * 1 9 5 1 . V . R . M ile s * P s y c h o l o g i c a l A s p e c t s o f A g in g * C h a p te r 2 8 i n E . V . O o w d ry 's P r o b le m s o f A g in g . B a ltim o r e * W illia m s a n d W ilk e n s * 1 9 3 9 * - 6 - o f e n v ir o n m e n ta l f a c t o r s * M o r e o v e r , jo b p e r fo r w a r " e i s n o t a s t a t i c c o n c e p t , b u t r e p r e s e n t s r a t h e r t h e c o n t in u in g o p e r a t io n c„, 1 1 s p e c i f i c f a c t o r s o f w h ic h i t i s com posed * M o st l a b o r a t o r y s t u d i e s , o n t h e o t h e r h a n d , c a n o n l y r e f l e c t o b s e r v a t i o n s m ade o v e r a s h o r t p e r io d o f tim e * The o p i n i o n s u r v e y s i n w h ic h e m p lo y e r s an d fo rem en a r e a s k e d f o r t h e i r e v a lu a t i o n o f w o rk ers* p e r fo r m a n c e s u f f e r fro m th e s h o r tc o m in g s o f s u b j e c t i v i t y a n d a l a c k o f s t a n d a r d i z a t i o n i n t h e c r i t e r i a e m p lo y e d . T he j o b p e r fo r m a n c e s t u d i e s u s in g p l a n t r e c o r d s h a v e t h e a d v a n ta g e o f b e in g o b j e c t i v e a n d r e f l e c t i n g t h e r e s u l t s o f a l l f a c t o r s i n th e jo b s i t u a t i o n . B u t a d e q u a te a n a l y s i s r e q u i r e s o u t p u t r e c o r d s b y a g e f o r a s u b s t a n t i a l num ber o f e m p lo y e e s e n g a g e d i n s i m i l a r jo b s * I t a l s o r e q u i r e s t h e s e l e c t i o n f o r s t u d y o f j o b s i n w h ic h s p e e d i s g o v e r n e d b y t h e w o r k e r s th e m s e lv e s * The d i f f i c u l t y o f o b t a in in g s u c h d a t a l i m i t s th e num ber a n d s c o p e o f t h e s e s u r v e y s c o n s id e r a b ly * I t i s , h o w e v e r , t h i s ty p e o f s t u d y , w h ic h i s m o st u s e f u l a s a n e v a lu a t i o n o f th e c o m p a r a tiv e o n - t h e - j o b p e r fo r m a n c e o f e m p lo y e e s o f d i f f e r e n t a g e s * 5 / 5 / One su c h s t u f y w a s c o n d u c te d f o r t h e B u r e a u i n 1 9 3 9 c o v e r in g som e t e x t i l e p l a n t s an d n o n f e r r o u s f o u n d r ie s in New E n g la n d * S e e I n f l u e n c e o f A g in g o n E m p loym en t O p p o r t u n i t i e s , M o n th ly L a b o r R e v ie w , A p r il 1 9 3 9 (p p . 7 6 5 -7 8 0 ). A n o th e r s t u d y o f t h e r e l a t i o n s h i p b e tw e e n a g e a n d p r o d u c t i v i t y o f p r o d u c t i o n wo r k e r s i n c i g a r f a c t o r i e s w a s d e v e lo p e d i n th e B u rea u * S e e I n d i v i d u a l P r o d u c t i v i t y D i f f e r e n c e s , BLS S e r i a l No* R* 1 0 li0 , F e b r u a r y 19U 0 (p p * 1 - 2 2 ) . F o r a n o t h e r B u r e a u s t u d y o f p e r fo r m a n c e an d a g e , s e e A b s e n te e is m a n d I n j u r y E x p e r ie n c e o f O ld e r W o r k e r s, M o n th ly L a b o r R e v ie w , J u ly 19U 8 (p p * 1 6 - 1 9 ) * - 7 - I n d i c a t o r s o f W ork P e r fo r m a n c e : D e f i n i t i o n s a n d M eth o d s o f M ea su rem en t Work p e r fo r m a n c e i s a n i n c l u s i v e te r m c o v e r in g m any a s p e c t s o f a n i n d i v i d u a l ' 8 w ork a c t i v i t y . I n s e l e c t i n g a p p r o p r ia t e i n d i c a t o r s o f w ork p e r fo r m a n c e f o r co m p a rin g w o r k e r s o f d i f f e r e n t a g e s , t h e f o l l o w i n g c r i t e r i a w e r e a p p lie d : 1. 2. 3. U* T h e i n d i c a t o r s m u st b e o b j e c t i v e l y m e a s u r a b le ; T h ey m u st b e c l e a r l y d e f i n a b l e ; T h ey m u st b e w o r k a b le i n te r m s o f b o th c o l l e c t i o n t e c h n iq u e s an d su b seq u en t p r o c e s s in g ; and T hey m u st b e a m en a b le t o th e d r a w in g o f p r a c t i c a l c o n c l u s i o n s . D i s c u s s i o n s w ith p l a n t a n d u n io n o f f i c i a l s an d e x a m in a tio n o f p l a n t r e c o r d s n a r r o w e d th e c h o i c e t o f o u r i n d i c a t o r s o f jo b p e r fo r m a n c e . T h ese w e r e o u tp u t p e r m a n -h o u r , a t t e n d a n c e , i n d u s t r i a l i n j u r i e s , a n d s e p a r a t i o n s . O th e r i n d i c a t o r s , s u c h a s q u a l i t y o f o u t p u t , d e p e n d a b i l i t y , and v e r s a t i l i t y , w e r e fo u n d l a c k i n g i n a t l e a s t o n e o f th e a b o v e c r i t e r i a . O u tp u t p e r M an-H our B a s i c t o a n y e v a lu a t i o n o f a w o r k e r 's p e r fo r m a n c e i s h i s p r o d u c t i v i t y . The d e f in it io n o f p r o d u c tiv ity u se d in t h is in v e s t ig a t io n i s h i s p h y s ic a l v o lu m e o f p r o d u c t io n p e r h o u r w o r k e d , i . e . h i s o u t p u t p e r m a n -h o u r . T h is i s p r o b a b ly t h e m o st f a m i l i a r o f t h e v a r io u s a s p e c t s o f a n i n d i v i d u a l ' s p r o d u c t i v i t y a n d i s a l s o t h e a s p e c t i n w h ic h g r e a t e s t i n t e r e s t i s c e n t e r e d . A n e c e s s a r y s t e p i n m e a s u r in g a n i n d i v i d u a l ' s o u t p u t p e r m a n -h o u r i s t o r e d u c e t o common u n i t s t h e v a r io u s p r o d u c t s h e m ay p r o d u c e . W here' a n i n d i v i d u a l i s e n g a g e d i n o n e p r o c e s s i n t h e m a n u fa c tu r e o f o n e p r o d u c t , h i s p r o d u c t i v i t y i s s im p ly t h e num ber o f p h y s i c a l u n i t s o f p r o d u c t h e p r o d u c e s d u r in g 1 h o u r . W here a n i n d i v i d u a l w o rk s o n a num ber o f p r o d u c t s , h o w e v e r , t h e r e i s a c h o i c e a v a i l a b l e f o r m e a s u r in g h i s p h y s i c a l o u t p u t . H is o u t p u t c a n b e m e a su r e d a s t h e t o t a l v a lu e o f a l l u n i t s h e p r o d u c e d . I n t h i s c a s e h i s p r o d u c t i v i t y i s t h e d o l l a r v a lu e o f h i s p h y s i c a l p r o d u c t io n . T h is v a lu e c a n b e m e a su r e d i n te r m s o f v a r io u s p r i c e s , b u t t h e p r i c e o f m o st im m e d ia te p r a c t i c a l a p p l i c a t i o n w o u ld b e t h e o n e r e l a t i n g t o th e f a c t o r y c o s t p e r u n i t o f p r o d u c t . T h e w o r k e r 's o u t p u t c a n a l s o b e m e a su r e d a s t h e t o t a l " n orm al" p r o d u c t io n tim e r e p r e s e n t e d b y h i s p h y s i c a l p r o d u c t io n . I n t h i s c a s e h i s p r o d u c t i v i t y i s t h e t o t a l p r o d u c t io n tim e e q u i v a l e n t s h e p r o d u c e d p e r h o u r . T h e se tim e e q u i v a l e n t s c o u ld b e d e te r m in e d fro m s t a n d a r d s b a s e d o n t im e s t u d i e s . H o w ev er, i t i s u s u a l l y n o t p o s s i b l e t o o b t a i n tim e r a t e s f o r a l l o p e r a t io n s o n a l l p r o d u c t s i n a p l a n t s i n c e som e p l a n t s c o n d u c t s t u d i e s o f s e l e c t e d o p e r a t io n s o n l y a n d m o s t p l a n t s a r e r e l u c t a n t t o f u r n i s h t h e tim e s ta n d a r d s t h e y u s e f o r v a r io u s o p e r a t i o n s . I n a d d i t i o n , r e c o r d s o f t h e a c t u a l num ber o f u n i t s o f e a c h p r o d u c t p r o d u c e d b y i n d i v i d u a l w o r k e r s a r e n o t r e a d i l y a v a i l a b l e i n m o st p l a n t s . C o n s e q u e n tly , a lt h o u g h t h i s m e a su r e o f o u tp u t w o u ld b e d e s i r a b l e , a s a p r a c t i c a l m a t t e r a n a l t e r n a t i v e m e a su r e m u st b e s e l e c t e d . - 8 - An a p p r o x im a tio n to m e a s u r in g o u tp u t i n te r m s o f p r o d u c t io n tim e i s t o u s e p ie c e w o r k e a r n in g s p e r h o u r . H e r e , t h e a s s u m p tio n i s m ade t h a t t h e t a s k p e r fo r m e d o n a p a r t i c u l a r p r o d u c t i s r e l a t e d , b y i t s p i e c e r a t e , to t h e tim e r e q u ir e d t o p e r fo r m t h e J o b . F o r e x a m p le , w h e r e a w o r k e r p e r fo z m s t h e sam e o p e r a t io n o n a v a r i e t y o f p r o d u c t s , a n y d i f f e r e n c e i n t h e t im e n o r m a lly r e q u ir e d t o c o m p le te t h e o p e r a t io n o n t h e v a r io u s p r o d u c t s w o u ld te n d t o b e r e f l e c t e d i n t h e v a r io u s p i e c e r a t e s p a id f o r th e p r o d u c t s . T h is a s s u m p tio n w as s u p p o r te d b y in f o r m a t io n o b t a in e d fr o m com p an y o f f i c i a l s i n t h e p l a n t s v i s i t e d . I t w a s p o i n t e d o u t t h a t tim e r e q u ir e d t o p e r fo r m a Job e n t e r s i n t o m o s t p i e c e - r a t e f o r m u la s . I n t h o s e c a s e s w h e r e p i e c e r a t e s m ig h t b e i n a c c u r a t e i n te r m s o f tim e r e q u ir e d f o r w o rk o n a g iv e n m o d e l, e a c h w o r k e r te n d e d to b e a l e r t t o t h e s e d i f f e r e n c e s a n d w o u ld i n s i s t o n r e c e i v i n g a n e q u i t a b l e s h a r e o f th e m ore d e s i r a b l e m o d e ls . I n a n y c a s e , i t c a n b e e x p e c t e d t h a t a n y in a c c u r a c y i n t h e d a t a o r i g i n a t e d i n t h i s w a y w i l l b e o f a random n a t u r e an d w i l l n o t a f f e c t o n e a g e g ro u p m ore s e r i o u s l y th a n a n o t h e r . O u tp u t p e r m a n -h o u r w as m e a s u r e d , t h e n , b y a v e r a g e s t r a i g h t - t i m e h o u r l y p ie c e w o r k e a r n in g s d u r in g t h e p e r io d s u r v e y e d . A l l e a r n in g s o n o v e r t im e w ork o r h o l i d a y w ork w e r e a d j u s t e d t o s t r a i g h t - t i m e l e v e l s b y r e m o v in g prem ium e a r n in g s . S i m i l a r l y , a l l tim ew o rk e a r n in g s w e r e rem o v ed fr o m t h e e a r n in g s o f i n d i v i d u a l s who w o rk e d b o t h o n p ie c e w o r k a n d tim ew o rk d u r in g th e s u r v e y p e r i o d . The m a n -h o u r s in c lu d e d r e f e r o n l y t o t h o s e h o u r s a c t u a l l y w o rk e d i n t h e p r o d u c t io n o f t h e o u t p u t . T h u s, a l l v a c a t io n h o u r s , p a id h o l i d a y s a n d o t h e r t im e p a id f o r b u t n o t w o r k e d , a s w e l l a s a l l h o u r s s p e n t o n tim e w o r k , w e r e e x c lu d e d fro m t h e h o u r s c o u n t e d . I n o r d e r t o u s e a v e r a g e h o u r ly e a r n in g s a s a m ea su rem en t o f o u t p u t p e r m a n -h o u r , i t i s n e c e s s a r y t o i n s u r e t h a t t h e r e a r e n o s p e c i a l r e s t r i c t i o n s a f f e c t i n g p ie c e w o r k e a r n in g s . T h e r e f o r e , i n t h e e x p l o r a t o r y w o r k , c e r t a i n J o b s w e r e e x c lu d e d f o r w h ic h m anagem en t im p o se d a l i m i t o n e a r n in g s i n o r d e r t o m a in t a in h ig h q u a l i t y s t a n d a r d s . 6 / L i m i t a t io n s o f C om paring E m p loy ed P ie c e w o r k e r s . I t i s r e c o g n iz e d t h a t t h e p e r fo r m a n c e o f p ie c e w o r k e r s m ay h o t b e e n t i r e l y r e p r e s e n t a t i v e o f a l l p r o d u c t io n w o r k e r s . Som e o f t h e f a c t o r s i n f l u e n c i n g t h e p r o d u c t i v i t y o f p ie c e w o r k e r s i n a s p e c i f i c a g e g ro u p m ay b e d i f f e r e n t fro m t h o s e i n f l u e n c i n g t h e p r o d u c t i v i t y o f a l l p r o d u c t io n w o r k e r s i n t h a t a g e g r o u p . F o r e x a m p le , t h e p a r t i c u l a r J o b s c l a s s i f i e d a s p i e c e - r a t e J o b s m ay p l a c e g r e a t e r e m p h a s is o n s p e e d , d e x t e r i t y , an d o t h e r c h a r a c t e r i s t i c s w h ic h a r e a f f e c t e d b y a g in g . P e r fo r m a n c e m e a s u r e s l i m i t e d t o t h e s e o c c u p a t io n s m ay 6 / I n t h e p l a n t s v i s i t e d t h e s e l i m i t s w e r e e x p r e s s e d i n te r m s o f a maximum num ber o f u n i t s p r o d u c e d d a i l y . - 9 - r e s u l t I n a c o m p a r is o n u n f a v o r a b le t o o l d e r w o r k e r s . D e s p i t e t h i s p o s s i b i l i t y , h o w e v e r , i t i s im p o r ta n t f o r t h o s e p l a n t s w h ere t h e m a j o r i t y o f th e p r o d u c t io n w o r k e r s a r e p a id o n p i e c e r a t e s ( o r som e o t h e r fo rm o f i n d i v i d u a l i n c e n t i v e s y s t e m ) t o h a v e in f o r m a t io n o n t h e c o m p a r a tiv e j o b p e r fo r m a n c e b y a g e grou p * I t m ay a l s o b e a r g u e d t h a t s i n c e o n l y e m p lo y e d p e r s o n s w e r e in c lu d e d i n t h e s t u d y , t h e o l d e r w o r k e r s w ho a r e s t i l l p r e s e n t i n t h e o c c u p a t io n s s t u d i e d a c t u a l l y r e p r e s e n t a s e l e c t e d g r o u p , s i n c e m any o f t h e y o u n g e r p e r s o n s w i l l h a v e g o n e i n t o o t h e r o c c u p a t io n s w h ic h w ere n o t in c lu d e d i n t h e s t u d y . How e v e r , t h e r e a r e a c t u a l l y tw o t y p e s o f s e l e c t i o n o p e r a t in g h e r e , w h ic h m ay b e e x p e c t e d t o c a n c e l e a c h o t h e r o u t t o som e e x t e n t . I n t h e f i r s t i n s t a n c e , t h e e x c e p t i o n a l l y s u p e r io r w o r k e r s m ay b e a ssu m ed t o h a v e g o n e i n t o b e t t e r p a y in g o c c u p a t i o n s . A t t h e sam e t im e , t h e m a r g in a l w o r k e r s , who c o u ld n o t m a in t a in t h e tHtHwnm s ta n d a r d s r e q u ir e d f o r t h e i r j o b s , w o u ld a l s o h a v e l e f t t o e n t e r o t h e r o c c u p a t i o n s . T h u s, t h e o l d e r w o r k e r s ' a v e r a g e o u t p u t r a t e s w o u ld b e i n f l u e n c e d b y t h e r e m o v a l o f t h e s e tw o e x t r e m e s , a n d , t h e r e f o r e , w o u ld b e l o g i c a l l y c o m p a r a b le w it h t h o s e o f t h e y o u n g e r g r o u p s . T h e r e a r e n o l i f e t i m e jo b h i s t o r i e s o f w o r k e r s i n t h e i n d u s t r i e s s t u d ie d w h ic h sh o w t h e e x t e n t t o w h ic h w o r k e r s e n t e r e i t h e r a s t im e o r p i e c e - r a t e w o r k e r s a n d m ove fro m o n e t y p e o f w ork w it h i t s a s s o c i a t e d p a y p r o c e d u r e t o a n o t h e r o v e r t h e i r l i f e s p a n , o r t h e e x t e n t o f m ovem ent fr o m p r o d u c t io n t o s u p e r v i s o r y o r e n t r e p r e n e u r i a l w ork o n t h e o n e h a n d , a n d t o c u s t o d i a l j o b s o n t h e o t h e r . T h e r e f o r e , i t w as n o t p o s s i b l e , w i t h i n t h e s c o p e o f t h e p r e s e n t s t u d y , t o d e te r m in e t h e e x t e n t t h e s e s i t u a t i o n s p r e v a i l i n t h e p l a n t s s u r v e y e d . S in c e t h e ir e f f e c t s a r e o f f s e t t i n g , th e n e t r e s u lt i s n o t b e lie v e d t o b e v e r y g r e a t. O b s e r v a t io n P e r i o d . The o b s e r v a t i o n p e r io d s e l e c t e d f o r o u t p u t p e r m an h o u r m e a su r e m e n t r a n g e ? fr o m U t o 8 w e e k s . T h is i s a co m p ro m ise b e tw e e n a p e r io d o f maximum l e n g t h , w h ic h w o u ld te n d t o e v e n o u t a t y p i c a l i n f l u e n c e s o f a te m p o r a r y n a t u r e , a n d a v e r y s h o r t p e r i o d , w h ic h w o u ld p e r m it t h e i n c l u s i o n o f a l a r g e num ber o f i n d i v i d u a l s ( s i n c e t h e s a m p le s in c lu d e d o n l y t h o s e e m p lo y e e s who w e r e w o r k in g d u r in g a l l o r n e a r l y a l l o f t h e o b s e r v a t i o n p e r i o d ) . A p e r i o d o f f u l l p r o d u c t io n w a s c h o s e n f o r o b s e r v a t i o n i n o r d e r t o m in im is e a n y i n f l u e n c e fro m i n d i v i d u a l s s h a r in g w o rk , w h ic h o f t e n o c c u r s d u r in g s l a c k p e r i o d s . T h ere i s , o f c o u r s e , t h e p o s s i b i l i t y t h a t d u r in g p e r io d s o f f u l l p r o d u c t io n t h e i n c e n t i v e f o r i n d i v i d u a l s t o m a x im iz e p r o d u c t io n i s r e d u c e d a f t e r a c e r t a i n e a r n in g s l e v e l i s a t t a i n e d . S h o u ld t h i s i n f l u e n c e a f f e c t a g e g r o u p s d i f f e r e n t l y , t h e m e a su r e w o u ld r e f l e c t n o t o n l y a n y r e l a t i o n s h i p w h ic h e x i s t e d b e tw e e n p r o d u c t i v i t y a n d a g e , t u t o t h e r f a c t o r s a s w e l l . O rou p s f o r D i r e c t C o m p a r iso n . I n o r d e r t o co m p a re jo b p e r fo r m a n c e b y a g e , t h e i n f l u e n c e o f f a c t o r s o t h e r th a n a g e m u s t, o f c o u r s e , b e e l i m i n a t e d . T h is m ea n s t h a t c o m p a r is o n s m u st b e l i m i t e d t o i n d i v i d u a l s who a r e s i m i l a r i n m any r e s p e c t s a n d w ho a r e e x p o s e d t o th e sam e w o r k in g c o n d i t i o n s . I n t h e c a s e o f p r o d u c t i v i t y , a s m e a su r e d b y a v e r a g e p ie c e w o r k h o u r l y e a r n in g s , d i r e c t com p a r i s o n s c a n b e m ade o n l y am ong w o r k e r s w it h a s i m i l a r d e g r e e o f e x p e r ie n c e - 10 - o n t h e s a n e s p e c i f i c j o b w i t h i n a p la n t * I f t h e b a s i c c e l l s a r e w id e n e d and w o r k e r s o n d i f f e r e n t j o b s o r o n t h e s a n e j o b i n d i f f e r e n t p l a n t s a r e com p ared d i r e c t l y , e x t r a n e o u s f a c t o r s s u c h a s d i f f e r e n c e s i n p a y s c a l e s , m a c h in e r y u s e d , and jo b r e q u ir e m e n ts w i l l b e in t r o d u c e d . I n t h a t c a s e d i f f e r e n c e s i n p r o d u c t i v i t y b e tw e e n a g e g r o u p s c o u ld b e t h e r e s u l t o f t h e i n f l u e n c e o f t h e s e f a c t o r s r a t h e r th a n a g e * D u r in g t h e p i l o t w o r k , d i r e c t c o m p a r is o n s w e r e m ade o n l y am ong i n d i v i d u a l s o f t h e sam e s e x who w e r e p e r fo r m in g th e sam e j o b o r s e r i e s o f o p e r a t io n s w i t h i n a p la n t * J o b t i t l e s fro m p e r s o n n e l r e c o r d s a lo n e w e r e n o t u s e d t o d e te r m in e a w o r k e r 's o c c u p a t io n b e c a u s e t h e s e r e c o r d s g e n e r a l l y d o n o t d e s c r ib e t h e o p e r a t i o n s a n i n d i v i d u a l p e r fo r m s . T he t i t l e s l i s t e d i n t h e p e r s o n n e l r e c o r d s f o r i n d i v i d u a l s w e r e co m p a red w it h t h o s e e n t e r e d o n t h e p t y r o l l r e c o r d s f o r c o n s i s t e n c y * A p p r o p r ia te p l a n t o f f i c i a l s w ere a l s o c o n s u lt e d a s t o w h e th e r i n d i v i d u a l s w e r e i n f a c t p e r fo r m in g t h e sam e o p e r a t io n s * T o a v o id c o m p a r is o n s b e tw e e n f u l l y e x p e r ie n c e d w o r k e r s a n d b e g in n e r s , e m p lo y e e s w it h l e s s t h a n 6 m o n th s' s e r v i c e i n a jo b w e r e e x c lu d e d fro m t h e o u t p u t p e r m a n -h o u r sa m p le* I t w as n o t a lw a y s p o s s i b l e b e c a u s e o f t h e l i m i t a t i o n o f p l a n t r e c o r d s , t o d e t e c t t h e e m p lo y e e s w h o , w h i l e m e e tin g t h e m inim um s e r v i c e r e q u ir e m e n t s , h a d b e e n t r a n s f e r r e d fro m som e o t h e r jo b * I n a d d i t i o n , t h e l e a r n i n g c u r v e f o r som e o c c u p a t io n s w i l l c o n t in u e t o r i s e f o r a l o n g e r p e r io d th a n 6 m o n th s* On t h e o t h e r h a n d , a c o n s i d e r a b l e p o r t i o n o f new e m p lo y e e s m ay h a v e h a d p r e v io u s e x p e r ie n c e e ls e w h e r e . A tte n d a n c e A tte n d a n c e , f o r p u r p o s e s o f t h i s s t u d y , h a s b e e n d e f i n e d a s t h e r a t i o o f t h e num ber o f d a y s a n i n d i v i d u a l i s p r e s e n t t o t h e num ber o f d a y s h e i s s c h e d u le d t o w ork * An i n d i v i d u a l w a s c o n s id e r e d a b s e n t w hen h e w a s aw ay fro m t h e jo b f o r a f u l l d a y o r m ore a t h i s ow n i n i t i a t i v e * L a y o f f s , h o l i d a y s , s h u td o w n s, a n d r e g u la r v a c a t io n s w e r e n o t c o u n te d e i t h e r a s d a y s a b s e n t o r d a y s s c h e d u le d * H o s t d i f f i c u l t i e s i n o b t a i n i n g a d e q u a te a t t e n d a n c e d a t a r e l a t e d t o l i m i t a t i o n o f p l a n t r e c o r d s . O f t h e p l a n t s s u r v e y e d , o n l y o n e m a in ta in e d i n d i v i d u a l a b s e n t e e is m r e c o r d s * F o r th e r e m a in in g p l a n t s , i t w a s n e c e s s a r y t o r e c o n s t r u c t i n d i v i d u a l r e c o r d s o f a t t e n d a n c e fro m d a i l y tim e c a r d s * lim e c a r d d a t a , h o w e v e r , d o n o t u s u a l l y d i s t i n g u i s h b e tw e e n a b s e n c e w h ich i s d u e t o p r o d u c t io n l a y o f f and a b s e n c e a t t h e e m p lo y e e 's i n i t i a t i v e * lb m ake t h i s d i s t i n c t i o n , th e d a i l y a t t e n d a n c e r e c o r d s f o r i n d i v i d u a l s w e r e co m p a re d , a n d w h e r e a s i g n i f i c a n t p r o p o r t io n o f w o r k e r s i n an o c c u p a t io n w e r e a b s e n t f o r a n i d e n t i c a l p e r io d , t h e y w e r e a ssu m ed a b s e n t a s a r e s u l t o f a p r o d u c t io n l a y o f f * B y u s i n g a p e r io d o f f u l l p r o d u c t io n a s th e o b s e r v a t i o n p e r io d f o r a t t e n d a n c e t h e i n f l u e n c e o f p r o d u c t io n l a y o f f s w a s b e l i e v e d t o b e m in im iz e d . I t i s a l s o d i f f i c u l t i n som e c a s e s t o d i s t i n g u i s h e x te n d e d a b s e n c e s fro m s e p a r a t io n s * Company p r a c t i c e s v a r y a s to t h e l e n g t h o f tim e an a b s e n t w o r k e r i s c a r r i e d o n t h e r o l l s * Som e c o m p a n ie s c o n s id e r a n i n d i v i d u a l s e p a r a t e d a f t e r 11 - 1 w eek o f a b s e n c e and d r o p h im fro m t h e i r r e c o r d s ; o t h e r c o m p a n ie s m a in ta in a n e m p lo y e e o n t h e c u r r e n t r o l l s u n t i l h e h a s b e e n g o n e f o r a c o n s i d e r a b l e l e n g t h o f t im e o r u n t i l h e in fo r m s th em d e f i n i t e l y t h a t h e i s n o t co m in g b ack * I n o r d e r t o o b t a i n a c o n s i s t e n t m e a su r e f o r a l l p l a n t s i n t h e p i l o t w o r k , com pany p a y r o l l r e c o r d s w e r e co m p a red o v e r a p e r io d o f tim e t o d e te r m in e w hen a n i n d i v i d u a l o n e x te n d e d a b s e n c e c o u ld b e c o n s id e r e d s e p a r a te d * O b s e r v a tio n P e r i o d . F o r a t t e n d a n c e , a s i n t h e c a s e o f o u tp u t p e r m anh o u r , t h e o b s e r v a t i o n p e r io d m u st b e lo n g e n o u g h t o a v o id a t y p i c a l s i t u a t i o n s * S e a s o n a l f a c t o r s , s u c h a s p a r t i c u l a r s p o r t s e a s o n s , m ay a f f e c t t h e a t t e n d a n c e o f i n d i v i d u a l s i n v a r i o u s a g e g r o u p s d i f f e r e n t l y * A ny m e a su r e l i m i t e d t o su ch p e r io d s d o e s n o t n e c e s s a r i l y y i e l d r e p r e s e n t a t i v e r e s u l t s * A p e r io d r a n g in g fro m 8 t o 1 2 w eek s d u r in g w h ic h i t w as b e l i e v e d s e a s o n a l f a c t o r s w o u ld b e m in im a l w a s s e l e c t e d f o r s t u d y . P a r t s o f t h a t p e r io d c o i n c i d e d w it h t h e o b s e r v a t i o n p e r io d f o r o u t p u t p e r m a n -h o u r* G ro u p s f o r D i r e c t C o m p a r iso n * I n c o n t r a s t t o o u t p u t p e r m a n -h o u r , t h e a t t e n d a n c e r a t e s o f i n d i v i d u a l s i n s p e c i f i c o c c u p a t io n s w ere b e l i e v e d t o b e d i r e c t l y c o m p a r a b le , y e t t h e r e a r e som e o c c u p a t i o n a l c h a r a c t e r i s t i c s w h ic h n o d o u b t i n f l u e n c e a tte n d a n c e * I t i s p r o b a b le t h a t p e r s o n s i n lo w e r p a id o c c u p a t i o n s m ay h a v e d i f f e r e n t a t t e n d a n c e m o t i v a t i o n s fr o m t h o s e i n h ig h e r p a id o c c u p a t io n s a n d a t t e n d a n c e c o m p a r is o n s b y a g e , ig n o r in g t h e s e d i f f e r e n c e s , m ig h t th e n r e f l e c t th e i n f l u e n c e o f t h e o c c u p a t i o n a l c o n c e n t r a t io n r a t h e r th a n age. To o b t a i n a t t e n d a n c e c o m p a r is o n s w h ic h r e f l e c t t h e i n f l u e n c e o f a g e a lo n e , o n l y i n d i v i d u a l s o f t h e sam e s e x i n t h e p l a n t o n th e sam e s y s t e m o f p a y m en t an d i n t h e sam e o c c u p a t i o n a l e a r n in g s l e v e l w ere d i r e c t l y com pared* 7 / I n d u s tr ia l I n ju r ie s N o n d is a b lin g a n d d i s a b l i n g i n j u r i e s w e r e s e l e c t e d f o r s t u d y i n t h i s e x p l o r a t o r y w ork* A lth o u g h s u f f i c i e n t d a t a c o u ld n o t b e o b t a in e d i n th e a c t u a l c o l l e c t i o n b e c a u s e o f t h e l i m i t e d c o v e r a g e , m any o f t h e p r o b le m s i n d e r i v i n g t h e s e i n d i c a t o r s fr o m e x i s t i n g p l a n t d a t a w e r e ex a m in ed * N o n d is a b lin g I n j u r i e s . A n o n d is a b lin g i n j u r y w a s d e f i n e d a s a n i n j u r y e x p e r ie n c e d i n t h e c o u r s e o f a n i n d i v i d u a l ' s w ork w h ic h d i d n o t i n v o l v e t h e l o s s o f a f u l l d a y o r m o r e . A lth o u g h t h e d e f i n i t i o n a p p e a r s r e l a t i v e l y s t r a i g h t f o r w a r d , t h r e e m a jo r p r o b le m s p r e s e n t t h e m s e lv e s w hen a t t e m p t in g t o d e r i v e a m e a su r e o f t h e f r e q u e n c y r a t e o f n o n d is a b lin g i n j u r i e s * F i r s t , p l a n t d e f i n i t i o n s o f w o r k -c o n n e c te d an d n o n w o r k -c o n n e c te d i n j u r i e s v a r y . P l a n t s w i t h b r o a d o v e r a l l m e d ic a l p r o g ra m s f o r t h e i r w o r k e r s do n o t m ake t h e sam e d i s t i n c t i o n s a s p l a n t s w it h l i m i t e d m e d ic a l p ro g ra m s* S e c o n d , p l a n t 7 / ih e b a s i s f o r c l a s s i f y i n g h ig h e r a n d lo w e r p a id o c c u p a t io n s i n t h i s s t u d y i s e x p la in e d i n a l a t e r s e c t i o n . ( S e e p p . U 7 -U 8 .) - 12 - r e q u ir e m e n ts w it h r e s p e c t t o t h e im m e d ia te tr e a tm e n t f o r n o n d is a b lin g i n j u r i e s a r e b y n o m ean s u n ifo r m . T h e s e r e q u ir e m e n ts a r e a l s o u s u a l l y r e l a t e d t o t h e t y p e o f g e n e r a l m e d ic a l c a r e p rog ra m p r o v id e d a s w e l l a s s a f e t y p r a c t i c e s and p o l i c i e s em p lo y ed i n t h e p l a n t . T h ir d , p l a n t p r a c t i c e s f o r r e c o r d in g n o n d i s a b l i n g i n j u r i e s v a r y c o n s i d e r a b l y . Som e p l a n t s r e c o r d a l l m in o r I n j u r i e s w h e r e a s o t h e r s r e c o r d o n l y t h e m a jo r o n e s . S h o u ld t h e s e d i f f e r e n c e s b e tw e e n p l a n t p r a c t i c e s a f f e c t a g e g r o u p s d i f f e r e n t l y , t h e v a l i d i t y o f a n y n o n d is a b lin g i n j u r y c o m p a r is o n s b e tw e e n a g e g ro u p s i s r e d u c e d . I t i s d o u b t f u l , b e c a u s e o f t h e s e l i m i t a t i o n s , t h a t n o n d is a b lin g i n j u r i e s c a n b e u s e d a s a n i n d i c a t o r o f c o m p a r a tiv e w ork p e r fo r m a n c e . D i s a b li n g I n j u r i e s . A d i s a b l i n g i n j u r y w a s d e f in e d a s a n i n j u r y e x p e r i e n c e d i n t h e c o u r s e o f a n i n d i v i d u a l ' s w ork f o r w h ic h a d a y o r m o re o f w o r k tim e w a s l o s t . I n t h i s c a s e , oom pany p r a c t i c e s c o n c e r n in g t h e d e f i n i t i o n and r e c o r d in g o f d i s a b l i n g i n j u r i e s a r e m uch m ore u n ifo r m . W orkm en 's c o m p e n s a tio n r e p o r t s g e n e r a l l y f u r n i s h s ta n d a r d in f o r m a t io n , an d t h e s e r e p o r t s a r e s i m i l a r f o r t h e v a r io u s S t a t e s . The d e f i n i t i o n o f a d i s a b l i n g i n j u r y i s u s u a l l y t h e sam e f o r m o st p l a n t s . On t h e o t h e r h a n d , t h e i n c i d e n c e o f d i s a b l i n g i n j u r i e s f o r a g iv e n e x p o s u r e p e r io d i s m uch lo w e r th a n t h a t o f n o n d is a b lin g i n j u r i e s s o t h a t a v e r y l a r g e sa m p le o f o b s e r v a t i o n s i s n e c e s s a r y t o a v o id - u n r e lia b le c o m p a r is o n s . T h is n e e d f o r a l a r g e s a m p le o f o b s e r v a t i o n s l i m i t s t h e u s e o f t h i s i n d i c a t o r t o v e r y l a r g e p l a n t s o r t o v e r y lo n g o b s e r v a t io n p e r i o d s . W here f o r m a k in g ( num ber o f (num ber o f i n d u s t r i a l i n j u r y d a ta a r e a v a i l a b l e , t h r e e m e a s u r e s c a n b e u s e d a g e g r o u p c o m p a r is o n s — t h e fr e q u e n c y r a t e , t h e s e v e r i t y r a t e h o u r s l o s t d u r in g a n e x p o s u r e p e r i o d ) , an d t h e a v e r a g e s e v e r i t y h o u rs l o s t p e r in ju r y ) • O b s e r v a t io n P e r i o d . The o b s e r v a t i o n p e r io d f o r t h e i n j u r y m e a su r e m u s t, o f n e c e s s i t y , b e l o n g e r th a n f o r e i t h e r t h e o u t p u t p e r m a n -h o u r o r a t t e n d a n c e m e a s u r e . B e c a u s e o f t h e r e l a t i v e l y s m a ll i n c i d e n c e f o r a l l a g e g r o u p s , i t i s n e c e s s a r y t o in s u r e t h a t a n y l a c k o f in c i d e n c e i s n o t m e r e ly t h e r e s u l t o f s e l e c t i n g a s h o r t s u r v e y p e r io d . A s m e n tio n e d a b o v e , th e i n j u r y m e a s u r e s r e q u ir e d a t a o n t h e num ber o f h o u r s w o rk e d ( t h e e x p o s u r e h o u r s ) d u r in g t h e o b s e r v a t i o n p e r io d . D a ta o n h o u r s w o rk e d b y i n d i v i d u a l s o v e r lo n g p e r i o d s a r e o f t e n d i f f i c u l t t o o b t a i n . M o st p l a n t s s u r v e y e d i n th e e x p lo r a t o r y w ork d id n o t m a in t a in su m m a ries o f h o u r s w o rk ed b y i n d i v i d u a l s o v e r p e r io d s lo n g e r th a n 2 w e e k s . I n t h e s e c a s e s , i t w a s n e c e s s a r y t o d e r iv e t h e t o t a l num ber o f h o u r s w ork ed fro m w e e k ly t i m e c a r d s . T h is i s q u i t e t im e c o n su m in g and c o s t l y , e s p e c i a l l y f o r an e x te n d e d i n j u r y p e r io d , and i t w a s fo u n d t o b e p r o h i b i t i v e i n t h i s i n v e s t i g a t i o n f o r p e r io d s lo n g e r t h a n 1 y e a r . Y e t , e x c e p t f o r v e r y l a r g e p l a n t s , a 1 - y e a r p e r io d d o e s n o t f u r n i s h s u f f i c i e n t d a ta t o p e r m it m e a n in g fu l c o m p a r is o n s b y age group. - 13 - I n d i v i d u a l e x p o s u r e h o u r s d a t a c a n b e e s t i m a t e d fro m o t h e r p l a n t r e c o r d s , b u t t h e s e p r o c e d u r e s m ay i n v o l v e a s s u m p tio n s w h ic h a r e n o t n e c e s s a r i l y v a l i d . O n e p r o c e d u r e a tte m p te d i n t h e p i l o t w ork i n v o lv e d d i v i d i n g t h e a n n u a l e a r n i n g s o f i n d i v i d u a l s b y t h e a v e r a g e s t r a i g h t - t i m e e a r n in g s f o r a r e p r e s e n t a t i v e p e r i o d . H o w ev er, u s e o f t h i s m eth o d i s l i m i t e d t o p e r i o d s d u r in g w h ic h i n d i v i d u a l s i n d i f f e r e n t a g e g r o u p s s h a r e e q u a l l y i n o v e r t im e w o r k . G rou p s f o r D i r e c t C o m p a riso n . T he fu n d a m e n ta l c o n s i d e r a t i o n i n m a k in g a n a n a l y s i s o f i n j u r y b y a g e g r o u p i s t o i n s u r e t h a t d i r e c t c o m p a r is o n s a r e m ade am ong w o r k e r s s u b j e c t e d t o e q u a l i n j u r y h a z a r d s . I t i s , h o w e v e r , v i r t u a l l y i m p o s s ib le t o c l a s s i f y e a c h w o rk e r a c c o r d in g t o i n j u r y h a z a r d . I n t h i s i n v e s t i g a t i o n a n a tte m p t w a s m ade t o d e r i v e d i r e c t c o m p a r is o n s b e tw e e n a g e g r o u p s f o r w o r k e r s c l a s s i f i e d a c c o r d in g t o t h e f o l l o w i n g c h a r a c t e r i s t i c s } s e x , h a n d o r m a c h in e o p e r a t i o n s , d e p a r tm e n t a n d p l a n t , a s a n a p p r o x im a tio n t o e q u a l iz i n g h a z a r d . S e p a r a t io n s S e p a r a t io n s a s d e f in e d i n t h i s s u r v e y i n c l u d e q u i t s , d i s c h a r g e s f o r c a u s e , r e t i r e m e n t , d e a t h , an d m i l i t a r y s e r v i c e am ong p r o d u c t io n w o r k e r s . E x c lu d e d a r e s e p a r a t i o n s f o r t h e c o n v e n ie n c e o f t h e e m p lo y e r s u c h a s l a y o f f s . The m e a su r e o b t a in e d i s t h e r a t i o o f t h e num ber o f s e p a r a t i o n s t o t h e t o t a l num ber o f p r o d u c t io n w o r k e r s i n d i f f e r e n t a g e g r o u p s . T h is m e a su r e a t t e m p t s t o a s c e r t a i n how m any o f a g r o u p o f w o r k e r s e m p lo y e d i n t h e p l a n t o n a g i v e n d a t e w ere s e p a r a t e d i n t h e f o l l o w i n g y e a r . I t w a s s e l e c t e d a s a p e r fo r m a n c e i n d i c a t o r b e c a u s e i t i s , t o a c e r t a i n e x t e n t , a m e a s u r a b le r e f l e c t i o n o f th e s t a b i l it y o f grou p s o f w o rk ers. A s m e n tio n e d a b o v e , p l a n t r e c o r d s s o m e tim e s d o n o t d i s t i n g u i s h e x te n d e d a b s e n c e s fro m s e p a r a t i o n s , b u t b y c o m p a rin g c u r r e n t a n d p a s t p a y r o l l s , i t i s p o s s i b l e t o o b t a in an i n d i c a t i o n o f w h e th e r a s e p a r a t i o n d id i n f a c t t a k e p l a c e . I n f o r m a t io n o n r e a s o n s f o r l e a v i n g , h o w e v e r , i s n o t a s r e a d i l y a v a i l a b l e . S e v e r a l a p p r o a c h e s w e r e a tte m p te d i n c l u d i n g i n t e r v i e w s w it h fo r e m e n , b u t b e c a u s e o f t h e p o s s i b i l i t y o f l a p s e o f m em ory o n t h e p a r t o f fo r e m e n , o n l y t h o s e p l a n t s w h ic h r e c o r d e d s p e c i f i c r e a s o n s f o r s e p a r a t i o n s w e r e i n c l u d e d . F o u r o f d ie p l a n t s s u r v e y e d d u r in g t h e p i l o t w ork m a in ta in e d s u c h r e c o r d s . G rou p s f o r D i r e c t C o m p a r iso n . S e p a r a t io n s a r e u s u a l l y g r e a t e r am ong a g r o u p o f r e l a t i v e l y new e m p lo y e e s th a n a g r o u p o f w o r k e r s w i t h lo n g y e a r s o f s e r v i c e . Com pany p e n s io n p r o g r a m s , co m m u n ity t i e s , and o t h e r f a c t o r s m ay i n f l u e n c e t h e d e c i s i o n o f a n e m p lo y e e w it h lo n g y e a r s o f s e r v i c e t o r e m a in w it h a com p an y, w h e r e a s a new e m p lo y e e m ay n o t b e a s s t r o n g l y a f f e c t e d b y s u c h f a c t o r s . S i m i l a r l y , d i f f e r e n c e s In p l a n t p o l i c i e s w i l l a l s o a f f e c t p r o d u c t io n w o r k e r s o f a g e g r o u p s d i f f e r e n t l y . - Ik - T h e I n f l u e n c e o f t h e s e f a c t o r s w a s ta k e n i n t o a c c o u n t i n d e s ig n in g t h e b a s i c d i v i s i o n s w i t h i n w h ic h c o m p a r is o n s b e tw e e n a g e g r o u p s c o u ld b e m ade* W ith in e a c h p l a n t , p r o d u c t io n w o r k e r s o f t h e sam e s e x w e r e d i v i d e d i n t o g r o u p s w it h m ore th a n 2 y e a r s ' a n d l e s s th a n 2 y e a r s ' s e r v i c e * I t w a s b e l i e v e d t h a t t h e s e c l a s s i f i c a t i o n s w o u ld r e d u c e t h e i n f l u e n c e o f f a c t o r s o t h e r th a n a g e a n d a t t h e sam e t im e a f f o r d s u f f i c i e n t o b s e r v a t i o n s t o w a r r a n t m e a n in g fu l c o m p a r is o n s * - 15 - I n d u s t r y a n d P la n t S e l e c t i o n B e c a u s e s t a t i s t i c s o n t h e p e r fo r m a n c e i n d i c a t o r s a r e m ore r e a d i l y a v a i l a b l e fr o m f i r m s e n g a g e d i n m a n u fa c tu r in g th a n fr o m n o n m a n u fa c tu r in g e s t a b l i s h m e n t^ t h i s i n i t i a l e x a m in a tio n w a s l i m i t e d t o m a n u fa c tu r in g i n d u s t r i e s * W ith i n m a n u fa c tu r in g , h o w e v e r , i t w a s p o s s i b l e t o e x a m in e p l a n t s w i t h i n o n l y tw o i n d u s t r i e s b e c a u s e o f t h e l i m i t e d r e s o u r c e s o f t h e p i l o t s tu d y * S e v e r a l c r i t e r i a w e r e u s e d t o s e l e c t t h e i n d u s t r i e s w i t h i n w h ic h p l a n t s w e r e s u r v e y e d * A l a r g e p r o p o r t io n o f e m p lo y e e s o v e r hS y e a r s o f a g e t o t o t a l e m p lo y e e s , t h e e x i s t e n c e o f som e fo r m o f i n d i v i d u a l i n c e n t i v e p a y m e n ts i n m o s t p l a n t s i n t h e i n d u s t r y , a n d th e im p o r ta n c e o f t h e in d u s t r y i n te r m s o f num ber o f w o r k e r s e m p lo y e d w e r e am ong th e f a c t o r s ta k e n i n t o c o n s id e r a t io n * I t w a s b e l i e v e d t h a t i n d u s t r i e s w it h a l a r g e p r o p o r t io n o f e m p lo y e e s o v e r U5 w o u ld i n c l u d e p l a n t s e m p lo y in g a s u f f i c i e n t num ber o f e m p lo y e e s i n t h e o l d e r a g e g r o u p s a s w e l l a s y o u n g e r a g e g r o u p s t o a f f o r d u s e f u l c o m p a r is o n s . A s m e n tio n e d a b o v e , t h e u s e o f i n d i v i d u a l i n c e n t i v e s y s te m o f p a y m e n ts i s n e c e s s a r y i n d e t e r m in in g i n d i v i d u a l o u t p u t d a ta * T h e f o o t w e a r a n d m e n 's c l o t h i n g i n d u s t r i e s w e r e s e l e c t e d f o r s t u d y fr o m t h e i n d u s t r i e s m e e tin g t h e s e r e q u ir e m e n ts * A c c o r d in g t o t h e 1950 C en su s B u r e a u R e p o r t o n I n d u s t r i a l C h a r a c t e r i s t i c s , 32.5 p e r c e n t o f a l l e m p lo y e e s i n t h e f o o t w e a r i n d u s t r y a n d 33*1 p e r c e n t i n th e a p p a r e l a n d f a b r i c a t e d t e x t i l e p r o d u c t s i n d u s t r y w e r e U5 y e a r s o f a g e a n d o v e r * I n a l l m a n u fa c tu r in g i n d u s t r i e s t h e p e r c e n t a g e w a s 31*1 S in c e th e m ein 's c l o t h i n g i n d u s t r y i s o n e o f t h e m o s t im p o r ta n t s e g m e n ts o f t h e a p p a r e l g ro u p an d h a s a m ore b a la n c e d d i s t r i b u t i o n b e tw e e n m a le a n d fe m a le e m p lo y e e s th a n o t h e r a p p a r e l i n d u s t r i e s , i t w a s s e l e c t e d a s th e s p e c i f i c i n d u s t r y t o b e ex a m in ed * Each of these industries is characterized also by incentive systems of payment for production workers* According to the Bureau of Labor Statistics' survey in 19t|6 on the extent of incentive pay in selected manufacturing in dustries, 89 percent of 3U7 footwear plants studied and 85 percent of plants manufacturing apparel had incentive systems of payment* 8/ Similarly, 65 percent of all production workers studied in the apparel Industry and 69 per cent of all workers studied in the footwear industry were on incentive pay* 9/ Most of the incentive plans were individual plans (usually straight piecework^ affording measures of individual output* 8/ Incentive Pay in American Industry, 19U5-U6, November 19U7 (pp* 535-538)* 9/ Idem* - 16 - Monthly Labor R e v ie w , T he g e o g r a p h ic a l c o n c e n t r a t io n o f t h e s e I n d u s t r i e s m ade i t p o s s i b l e t o l i m i t p l a n t v i s i t s d u r in g t h e p i l o t w ork t o t h e le w En g l a n d a n d M id d le A t l a n t i c r e g i o n s . I n 195k , 69 p e r c e n t o f a l l e s t a b l i s h m e n t s i n t h e U n it e d S t a t e s m anu f a c t u r i n g m e n 's s u i t s a n d c o a t s e m p lo y in g 60 p e r c e n t o f t h e t o t a l p r o d u c t io n w o r k e r s w e r e l o c a t e d i n t h e s e r e g i o n s . I n f a c t , o v e r t w o - f i f t h s (%1 p e r c e n t ) o f t h e e s t a b l i s h m e n t s a n d o n e - f o u r t h o f t h e p r o d u c t io n w o r k e r s i n t h e in d u s t r y w e r e i n o n e S t a t e , Hew Y o r k . O f t h e 1 ,2 0 0 f o o tw e a r e s t a b l i s h m e n t s i n t h e U n it e d S t a t e s i n 195% , a p p r o x im a te ly 6 0 p e r c e n t w e r e l o c a t e d i n t h e s e r e g i o n s , w i t h 99 p e r c e n t o f t h e t o t a l p r o d u c t io n w o r k e r s i n t h e i n d u s t r y . I n t h i s i n d u s t r y m ore th a n 36 p e r c e n t o f t h e e s t a b l i s h m e n t s a n d 29 p e r c e n t o f t o t a l p r o d u c t io n w o r k e r s w e r e l o c a t e d i n M a s s a c h u s e tt s a n d New Y o r k . 1 0 / A lth o u g h t h e r e m ay h a v e b e e n som e c h a n g e s i n t h e g e o g r a p h ic a l c o m p o s it io n o f t h e s e i n d u s t r i e s s i n c e 199%, ii* 1 * d o u b t f u l t h a t a n y m arked s h i f t h a s o c c u r r e d . P l a n t s w e r e s e l e c t e d f o r s t u d y fr o m a l i s t o f e s t a b l i s h m e n t s i n t h e s e I n d u s t r i e s , i n t h e r e g i o n s m e n tio n e d . O n ly l a r g e - s i z e p l a n t s w it h p e r s o n s i n a l l a g e g r o u p s d o in g t h e sam e w o rk c o u ld f u r n i s h a d e q u a te c o m p a r is o n s . C o n s e q u e n t ly , p l a n t s w h ic h h a d m ore t h a n kOO p r o d u c t io n w o r k e r s w e r e i n c l u d e d . A l l t h e s e r e q u ir e m e n ts r e s u l t e d i n a l i m i t e d num ber o f p l a n t s fr o m w h ic h t h e sa m p le c o u ld b e d r a w n . S e l e c t i o n o f t h e p l a n t s s u r v e y e d w a s n o t m ade b y a random p r o c e s s . V i s i t s w e r e m ade t o p l a n t s a b o u t w h ic h t h e B u rea u h a d som e k n o w le d g e c o n c e r n in g t h e n a t u r e o f t h e r e c o r d s a n d t h e t o t a l num ber a n d d i s t r i b u t i o n o f e m p lo y e e s , b y s e x . T he m a in e m p h a s is o f t h e w o rk w a s t e s t i n g t e n t a t i v e q u e s t i o n n a i r e s a n d d e v e lo p in g m ea su rem en t t e c h n i q u e s . D u r in g t h e p i l o t w o rk 10 p l a n t s w e r e v i s i t e d , 2 o f w h ic h w e r e e l i m i n a t e d fro m t h e s a m p le —1 b e c a u s e i t e m p lo y e d o n ly a sm a ll, num ber o f p ie c e w o r k e r s , an d t h e o t h e r b e c a u s e i t m a in ta in e d in a d e q u a te p l a n t r e c o r d s f o r t h i s s t u d y . 3 0 / U . S . B u rea u o f t h e C e n s u s , A d v a n ce R e p o r t, 193% C e n su s o f M a n u fa c tu r e s . - IT - D a ta C o l l e c t i o n P r o c e d u r e s T h e a m o u n t a n d c o m p le x it y o f t h e in f o r m a t io n t o b e o b t a in e d fro m t h e p l a n t s f o r t h i s s t u d y p r e c lu d e d c o n d u c t in g a m a ll s u r v e y . T he l o s s o f c o n t r o l o v e r t h e t y p e o f d a t a c o l l e c t e d i n a m a il s u r v e y m o u ld s e r i o u s l y l i m i t t h e a c c u r a c y o f a n y d e r iv e d r e s u l t s . I n a d d i t i o n , t h e l e n g t h o f tim e r e q u ir e d f o r t h e p a r t i c i p a t i n g e s t a b lis h m e n t t o a s s e m b le a n d f u r n i s h t h e d a t a w o u ld r e d u c e t h e c h a n c e s f o r c o o p e r a t io n . I n m any c a s e s , t h e n a t u r e o f p l a n t r e c o r d s w o u ld n o t p e r m it a s s e m b lin g t h e d a t a d i r e c t l y b u t w o u ld r e q u i r e d e r i v i n g t h e in f o r m a t io n fro m a v a r i e t y o f s o u r c e s u s u a l l y m a in ta in e d f o r o t h e r p u r p o s e s . C o n s e q u e n tly , p e r s o n a l v i s i t s b y t r a i n e d a g e n t s w e r e r e q u i r e d . A l l d a t a o b ta in e d in t h is in v e s t ig a t io n w ere c o lle c t e d by p r o j e c t s t a f f v i s i t i n g th e p l a n t s . On th e a v e r a g e , th e tim e n e e d e d to o b t a i n th e d a t a f o r a p l a n t em p l o y in g 500 p i e c e - r a t e w o r k e r s w a s a b o u t o n e m an-m on th* A s c h e d u le f o r c o l l e c t i n g t h e d a t a w a s d e v e lo p e d a n d t e s t e d i n t h e p l a n t s v i s i t e d * 1 1 / I t c o n s i s t e d o f tw o p a r t s — a q u e s t i o n n a i r e a n d a s e t o f s ta n d a r d i z e d w o r k s h e e t s . T he q u e s t i o n n a i r e r e q u e s t e d in f o r m a t io n o f a g e n e r a l n a t u r e c o n c e r n in g t h e r e c o r d s a n d p la c e m e n t p r o c e d u r e s o f t h e p l a n t . A n sw e r s t o t h e it e m s o n t h e q u e s t i o n n a i r e p e r m it t e d t h e a g e n t t o s e l e c t ( w i t h i n c e r t a i n l i m i t s ) t h e a p p r o p r ia t e p e r io d f o r s t u f y a n d f u r n i s h e d a g u id e t o t h e p a r t i c u l a r r e c o r d s o u r c e s i n t h e p l a n t w h ic h s h o u ld b e e x a m in e d i n o r d e r t o d e r iv e t h e r e q u ir e d d a ta * T h e q u e s t i o n s o n p la c e m e n t p r o c e d u r e s w ere d e v e lo p e d to a s c e r t a i n , i f p o s s i b l e , som e o f t h e f a c t o r s w h ic h m ig h t b e a s s o c i a t e d w it h d i f f e r e n t r e s u l t s fr o m d i f f e r e n t p l a n t s * A p l a n t w h ic h h a d p h y s i c a l , a p t i t u d e , a n d jo b e x a m i n a t i o n s a s w e l l a s s p e c i f i c p r o g ra m s f o r r e t r a i n i n g a n d r e a s s ig n m e n t m ig h t w e l l h a v e a d i s t i n c t l y d i f f e r e n t p a t t e r n o f jo b p e r fo r m a n c e an d a g e r e l a t i o n s h i p s fro m a n o t h e r l a c k i n g su c h p r o c e d u r e s . N on e o f t h e p l a n t s i n c lu d e d i n t h e p i l o t i n v e s t i g a t i o n h a d s p e c i f i c p r o g ra m s a lo n g t h e s e l i n e s * The worksheets were designed for recording personnel information and data on each of the performance measures separately for each individual. T h ey w e r e c o n s t r u c t e d f o r u s e i n e i t h e r m a ch in e o r h a n d p r o c e s s i n g o f th e d a t a , a n d w e r e a d a p ta b le t o d i f f e r e n t t y p e s o f p l a n t r e c o r d s . I n th e e x p l o r a t o r y w ork v a r io u s fo r m s w e r e a t te m p te d an d i t w a s fo u n d t h a t t h e u s e o f a s e p a r a t e c a r d f o r e a c h w o r k e r w a s t h e m o st e f f i c i e n t p r o c e d u r e f o r t r a n s c r i b i n g t h e d a t a fr o m com pany r e c o r d s * W o r k s h e e t 1 ( s e e p . 66) w a s t h e b a s i c w o r k s h e e t o n w h ic h d a t a f o r a l l m e a s u r e s w e r e r e c o r d e d . I t c o n s i s t s o f f o u r m a jo r s e c t i o n s c o v e r in g p e r s o n n e l i n f o r m a t io n , e a r n in g s d a t a , a t t e n d a n c e , a n d i n d u s t r i a l i n j u r y d a ta g e n e r a l l y d e r iv e d fr o m d i f f e r e n t s e t s o f r e c o r d s * P e r s o n n e l a n d s e p a r a t i o n s d a t a w e r e u s u a l l y a v a i l a b l e fr o m p e r s o n n e l r e c o r d s a lt h o u g h o c c u p a t i o n a l t i t l e s w e r e n o t n e c e s s a r i l y a c c u r a t e . E a r n in g s a n d h o u r s d a t a w e r e u s u a l l y a v a i l a b l e n / A c o p y o f t h i s s c h e d u le w ith a co o m p a n y in g i n s t r u c t i o n s f o r a g e n t s i s r e p r o d u c e d i n t h e a p p e n d ix o f t h i s r e p o r t * - 1 8 - d i r e c t l y fro m p a y r o l l a n d p ro d u e t i o n r e c o r d s , b u t i n o r d e r t o o b t a i n i n f o r m a tio n o n o n l y p ie c e w o r k h o u r s a n d e a r n in g s , i t w a s so m e tim e s n e c e s s a r y t o com p u te t h e s t r a i g h t - t i m e p ie c e w o r k e a r n in g s o f e a c h i n d i v i d u a l fro m t h e d a i l y p i e c e t i c k e t s tu r n e d in d u r in g t h e s u r v e y p e r i o d . A tte n d a n c e d a ta (d a y s w o rk e d a n d d a y s s c h e d u le d ) u s u a l l y h a d t o b e co m p u ted fr o m i n d i v i d u a l t im e c a r d s . N o n d is a b lin g i n j u r y d a ta w e r e a v a i l a b l e fro m d is p e n s a r y o r n u r s e ' s r e c o r d s w h e re t h e y e x i s t e d . D i s a b li n g i n j u r y d a t a c o u ld b e d e r iv e d fro m w o rk m en 's c o m p e n s a tio n r e c o r d s . W o r k sh e e t 2 ( s e e p . 6 7 ) w a s d e v e lo p e d t o s u p p le m e n t t h e p r o d u c t i v i t y in f o r m a t io n o b t a in e d o n w o r k s h e e t 1 . I t w a s d e s ig n e d to t e s t , i f p o s s i b l e , t h e r e l a t i o n s h i p b e tw e e n p i e c e r a t e s on v a r io u s p r o d u c t s w i t h s ta n d a r d t i m e s . D u r in g t h e p i l o t w o r k , i t w a s h o p e d t h a t t h e a d d i t i o n a l d e t a i l w o u ld b e u s e f u l e s p e c i a l l y w hen i n d i v i d u a l s p e r fo r m e d a v a r i e t y o f o p e r a t io n s o n m any p r o d u c t s . I t w a s n o t p o s s i b l e , h o w e v e r , d u r in g th e p i l o t w ork t o o b t a i n in f o r m a t io n o n w o r k s h e e t 2 a n d th e s t a t i s t i c a l r e s u L t s r e p o r t e d h e r e w e r e d e r iv e d e n t i r e l y fro m d a ta r e c o r d e d o n w o r k s h e e t 1 . Statistical Methods The statistical procedures applied to the raw data were, in essence, those necessary for combining a large number of individual observations Into broader findings. The results of the study were intended to show: 1. 2. 3. The performance of several age groups as compared with each other; Any differences in the influence of age on the performance of men and women in various types of jobs and industries; and Individual variation in the performance of workers. The information recorded during the plant visits would not yield these results unless the raw data were processed further. The procedures used for the four types of performance indicators, although similar, were not identical and are presented separately for each indicator. Prior to discussing the particular methods applied, it might be well to indicate the age groups which were selected for comparison. Age Groups In order to secure results of maximum precision, it would have been desirable to classify workers in narrowly defined age groups. Classification of workers in 5-year age groups was attempted for this study but the sample was too small to yield meaningful results. Consequently, for all of the performance measures, workers were classified into 10-year age groups. These were under 25, 25-31:, 35-UU, U5-5U, 55-61:, and 65 and over. In a larger scale survey, the use of 5-year groups might prove feasible. Output Per Man-Hour As mentioned earlier, in order to obtain meaningful measures of output per man-hour, the basic groups for direct comparison consisted of experienced employees of the same sex working at the same specific occupation in a plant. Each of the plants surveyed, however, was characterized by a large number of different occupations with relatively few individuals in each occupation. In many occupations, only 2 or 3 of the age groups were represented. Therefore, if all comparisons had been made only between individuals in the same occu pations, the results would have been extremely limited. It was necessary to apply some procedure which would convert the output per man-hour scores (average hourly piecework earnings) of workers in specific occupations into some measure which would, thereafter, be entirely independent of the particular occupation in which the workers were found. The procedure adopted consisted of converting each output score for workers in the same occupation into an index. The 35-U1: age group for the occupation was assigned an index of 100, and the index of each of the other age groups was simply the ratio of the average score of that age group to the — 2 0 — average score of the 35>-iiU year group* 12/ Thus, a comparable measure was derived for each age group, each measure reflecting the relative performance of a given age group as compared with the corresponding 35-Ui year group, By transforming the scores of age groups into indexes, the possible distorting influence of variations in absolute pay levels in different operations or in different plants was eliminated. The measures could now be treated as a homo geneous group of indicators, and it was no longer necessary to be concerned with actual scores of individuals, nor the plant in which they worked. Occupational Groups. The indexes, up to this point, represented only output measures of workers in specific occupations within plants. In order to derive results which would reflect larger numbers of individuals than were available in these fine occupations, some means had to be found for combining the indexes. This was done by establishing occupational groups in which the effect of factors other than age could be expected to be fairly uniform for all age groups. In summarizing the data, indexes for workers in specific occupations were grouped according to the following characteristics: 1. 2. 3. U. Sex; Hand or machine occupations 13/; Higher or lower paid occupations 13/; and Industry. If these distinctions had not been made, then differences between the index of one age group and another might be due, in part, to the different distribution of these characteristics in the two age groups. Consequently, through the use of these classifications, valid comparisons among age groups could be obtained. Procedure for Combining Indexes of Specific Occupations. As mentioned above, each of the age group indexes for the specific occupations was derived from the scores of individuals in a particular age group and the correspond ing base group within a single plant. Some were based on a very small number of individuals in both the age and base groups whereas others represented larger groups. In combining the age group indexes for a specific occupation to obtain a measure for an occupational group, it was necessary to assign a weight to each index reflecting its relative importance in the measure for the occupa tional group. This weighting procedure took into account the number of work ers in the age group as well as the number of workers in the base group for each occupation. 1k / 12/ A procedure was also applied which permitted the use of the 25-3U year group transformed to the 35>-UU year group as the base. This method en abled the use of more observations. It is described more fully in the appendix. (See p. U9 * ) 13/ The basis for classifying occupations into higher or lower paid and hand or machine operations is discussed in the appendix. (See pp. U7-U8.) ill/ The formula for these weights is included in the appendix. (See - 2 1 - Combining Indexes of Occupational Groups* In addition to lndexe 8 for specific and combined occupation groups, i t w a s considered desirable to obtain more generalized indications of the relative performance of the various age groups. For example, age-group indexes were obtained for all male employees in the clothing plants, whether they mere working at hand or machine operations, or in higher or lower paid Jobs. In order to derive these indexes a procedure was required to insure that the influence of factors other than age would be constant for all age groups. The simplest method for accomplishing this was to assign, to each occupational group index, a constant weight for all age groups. When combined through the use of these weights, the four occupational groups indexes yielded an index which was not influenced by the shifting proportion of, sa$ higher and lower paid occupations, from one age group to another. The weighting scheme actually used was based on the total number of workers of all ages within an occupational group. Individual Variation. As mentioned earlier, one of the purposes of this study, in addition to measuring the relationships between age and work per formance was to determine the extent of individual variation within each age group. It is important to know whether the index derived for a particular age group reflected the performance of individuals whose output scores showed considerable uniformity, or whether, on the other hand, their scores varied widely about the average for that group. An employer, fbr example, would logically give greater consideration to the characteristics of an individual applicant rather than to his age, if he knew that performance differences between age groups is less than the individual variation in any one age group. The measure of dispersion which was employed reflects the difference between the age group average and the individual scores for each occupation. The actual measure was the coefficient of variation, which is expressed as a percentage of the group score. As in the case of the age group indexes, the dispersion measures for the specific occupations were combined to obtain a measure for the occupational group. Again, it was desirable to combine these dispersion measures with weights which would reflect their relative importance in the combined measure. In this case, the weight applied took into account only the number of wo liters in the age group for the occupation. Similarly, it was considered useful to obtain a dispersion measure for combinations of the occupational groups. The same weighting procedure as used in combining the Indexes of output per man-hour for the specific occupations was employed. - 2 2 - Attendance As noted above, the basic group In the attendance comparisons was not the specific occupation, as in the case of output per man-hour, but rather the type of occupation (higher or lower paid)* It was believed that in the two industries covered the specific occupation had little bearing on the attendance rate of an employee* Thus, to obtain comparable attendance rates for the various age groups, individuals were grouped according to sex, plant, and occupational earnings level* For each of these classifications, age group indexes were derived by dividing the average attendance rate for an age group b y the average rate of the 35-UU year group* 15/ In this case, as in output per man-hour, a common measure was derived from all rates reflecting the relative performance of a given age group as compared with the corresponding 3S-UU year group* This approach yielded indexes which included a considerably larger number of workers than those obtained from single occupations in the output per man hour indexes* However, each of these series referred to individual plants* What was desired were results which would cover broader groups* Therefore, plant attendance indexes for each age group were combined in a manner similar to that used for combining output per man-hour indexes for specific occupations* The weight assigned to each plant in this case took into account the number of workers in the age group, the number of workers in the base group, and the number of scheduled workdays of the survey period* 16/ It was also considered useful to derive attendance measures for a com bination of these groups* These, like the combinations of output per man-hour occupational groups, required a weighting procedure which would not permit the influence of factors other than age to enter into the measure* A similar fixed weighting system was employed which assigned the same weight to each age group index pertaining to the same earnings level* Dispersion measures were not calculated for attendance, since it became evident at an early stage that such measures would have limited usefulness* The average attendance rate was very close to the maximum attainable rate (100 percent) indicating there could be only small differences in magnitude above the average* 15/ A procedure similar to that indexes making use of the 25-3U group carried out here* For details of the 16/ The formula for this weight employed for the output per man-hour in addition to the 35-UU year group was procedure, see appendix p. 1$, is shown in the appendix* (See p. 1#*) - 23 - Industrial Injuries In order to minimize the influence of factors other than age, as noted earlier, basic comparisons of injury experience should be made among indivi duals of the same sex within the same plant performing the same type of operations (hand or machine), in attempt was made to draw such comparisons. However, industrial Injuries occur infrequently and to draw such comparisons either a large number of workers or a long observation period for a smaller number of workers would be required. In the plaints surveyed there had been no injuries in many age groups. These groups, therefore, had injury rates of zero. The use of age group indexes, consequently, was found to be impractica ble because base groups for several series had zero injury rates. Sven if there had been injury incidence in all base groups, comparisons with zero rates for other age groups would be misleading since, given a longer period of observation or a large number of workers, it is probable that a zero rate would not occur. In view of the extremely limited nature of the data obtained, only the incidence of injuries for several of the plants visited rather than the indexes, are shown in this report. These are included for illustrative purposes. Separations The basic groups for comparison were established in terms of plant, sex, and length of service, and age group indexes were derived. As in the case of output per man-hour and attendance,the age group separation rates were related to the separation rate for the corresponding 35 -U* year age group. Combinations were made of indexes of each of the basic comparison groups in a manner similar to that used for the other measures. The weight applied to each index took into account the number of workers in the age group, the number of workers In the base group, and the length of the separation obser vation period in the plant. Separations, like injuries, occur infrequently, and consequently, require a greater number of observations for adequate measures than productivity or attendance. Since the separations data obtained in this survey were very limited, the indexes shown are primarily illustrative. - 2h - jjMwfl-lngH in the Plants Surveyed The measures of work performance Included here were derived from data obtained in plants visited daring the exploratory work. The results show per formance b y age group only for the plants surveyed, and generalizations should not be drawn with respect to the two industries included in the samples. In addition to the smallness of the sample, the method of plant selection did not attempt to achieve industry representativeness. It was not the purpose of this investigation to compile statistics which would provide definitive results for the two industries, although certain limited findings were anticipated. As indicated elsewhere in this report, the main emphasis was on developing performance indicators and testing measurement techniques. The findings presented here reflect the experience of piece-rate pro duction workers employed in k plants in the men's clothing industry and k plants in the footwear Industry. All plants were located in the Hew England and Kiddle Atlantic regions and ranged in size from 500 production workers to more than 2,500. Data for selected periods in 1955 were collected. The periods chosen were those of substantially full production in the plants studied. Output Per Man-Hour Output per man-hour data were obtained for 2,217 production workers— 933 in the footwear plants and 1 ,28 k in the clothing plants* Separate results are shown for men and women employed in the two groups of plants (tables 1 and 2 ). They are further broken down into earnings level groups (tables 3 t k, 5, and 6 ) and according to hand and machine occupations (tables 7 , 8 , 9 , and 10 ). The age span surveyed ranges from under 25 years of age to 65 years and over for the detailed job classifications. For the combined groups, this range was narrowed to the age groups 25 to 65 only, because of the Inadequate number of observations which could be obtained in the youngest and oldest age groups in some of the detailed job categories. Men and Women. The productivity of both male and female pieceworkers in the footwear and clothing plants studied did not vary with age until after age 5k (tables 1 and 2). The anal3 differences between the indexes for age groups under 55 were not statistically significant. After that age the figures for most groups show a decline which, although statistically significant, was not of serious proportions. In no case did the performance of any 55 -6 k year group fall below 90 percent of the base group index. And one group of older workers (women aged 55 -6 k in the footwear plants) in fact performed as well as any younger group of women. The output indexes for men in both the footwear and clothing plants show slight increases between the youngest groups (2 5 -3 k) and the base groups. These apparent increases, however, are not statistically significant. Similarly, the small differences observed between the base groups the corresponding k5-5k year groups are not significant. After age 5k, the decline noted above occurs. - 25 - Table 1.— Indexes of output per man-hour for pieceworkers in four footwear establishments, by sex and age grot?) (Age group 35-14**100) Women Men Age group y Number of workers Index Coefficient of variation (percent) Ntrmber of workers Index Coefficient of variation (percent) 25-3U.... 91* 97.3 18 .8 97 10 0 .8 35-14;.... 163 10 0 .0 ll;.0 161* 10 0 .0 18 .2 1 U .6 1*5-51*..... 123 97*8 1 U .0 129 99.0 13.1; 98 2 / 9 2 .1 13.3 60 99.6 1 1 .1; 55-61*.... 1/ Two age groups, under 25 and 65 and over, are excluded because the number of observations was considered insufficient. Cf. table 11* 2/ This index is significantly different from 100 in the sense that, if there” were really no difference between the age group and the base group, a difference as great as this would be obtained less than one time in twenty on repeated sampling* Table 2*— Indexes of output per man-hour for pieceworkers in four clothing establishments, by sex and age group ____________ _________________ (Age group 35-UU=100)__________________________ Womerl Men Age group 1 / Humber of workers Index Coefficient of variation (percent) Number of workers Index Coefficient of variation (percent) 25-3U.... 52 98.6 7.1 10 0 99.3 2 2 .2 35-W;.... 82 10 0 .0 1 5 .0 220 10 0 .0 U5-5U..... 51 100.5 1 U. 1 387 98.U 19 .8 18 .2 2 / 9 1.8 20 .8 279 2 / 9 0 .2 1 9 .2 55-61;.... no \ f Two age groups, under 25 and 65 and over, are excluded because the number of observations was considered insufficient* Cf. table 12* 2/ This index is significantly different from 100 in the sense that, if there were really no difference between the age group and the base group, a difference as great as this would be obtained less than one time in twenty on repeated sampling* - 26 - Although the output pattern for men is similar in both industries, the patterns for women differ. The indexes for women in the footwear plants show insignificant variation between the ace croups. In the clothing plants, how ever, the indexes for women exhibit a pattern similar to that of the indexes for men— stable output until age 5^-, after which there is a decline. In addition to comparing the average productivity of age groups, it is useful to examine the variation in performance among individuals within each age group. The measure of this variation is provided by the coefficient of variation. 17/ As shown in the tables, the coefficients of variation exhibit no pronounced tendency to vary consistently with age. Although the measures for both men and women in the footwear plants decline slightly with age, these differences are small. For the clothing plants, the dispersion measures appeal to increase for men after age 3^ and again after age 5 k . They show a slight decline for women after age 3^> remaining stable thereafter. The coefficients do, however, indicate considerable individual vari ability within age groups. Also, individual dispersion appears to be some what greater in the clothing plants than in the shoe plants. The average coefficient of variation for men of all ages in the footwear plants was the same as for women— 15 percent. In the clothing plants the average coefficient for all men was 1 7 percent and for women 19 percent. When the dispersion measures for the age groups are examined together with the output per man-hour indexes, it is evident that the differences in performance among Individuals within age groups are usually more important than differences between age groups. For example, men between the ages of 55 and 6h in the footwear plants had an index of 92 and a dispersion measure of 13 percent, indicating that roughly one-third of the individual scores can be expected to be outside the index values of 10^ and 80. More interesting, perhaps, is the Inference that approximately 25 percent of the men, aged 55-6 k 17/ The coefficient of variation is used to express the relative vari ability of groups of data. It is calculated by dividing the standard devi ation b y the mean, and indicates the relationship between the value of the mean and the distance from the mean within which a specified proportion of the observations will lie, if the distribution is approximately normal. For example, if the average index of an age group were 90 , and the coefficient of variation 10 percent, then about two-thirds of the indexes would lie between 8 l.O and 99*0 (these limits being the mean plus and minus 10 percent of the mean). This assumes, again, that the form of the distribution is not far from normal. There is evidence supporting the view that this will be the case in output per man-hour scores. See Individual Productivity Differences, BIS Serial Bo. R. 10lf0, February 19 I10 , (pp. 18 and 19 ). 27 - in the footwear plants vould be expected to produce more than the average produced b y the 3 5 - ^ year group— the peak performance group. Thus, although in most cases the indexes for the 55 -6H year groups are somewhat lower than those for other age groups, the sizable variation observed vithin all age groups implies that too much emphasis should not be placed on the group Indexes as indicators of individual performance. Insofar as practical Implications are concerned, these data suggest that an employer, in considering an applicant for employment, should evaluate the person as an individual rather than attempt to draw conclusions from his chronological age. Higher and Lower Paid Occupations. The manner in which a are is associated with the performance of workers in higher and lower paid jobs is indicated in tables 3, k, 5 , and 6 . Since the earnings level of a job often reflects its skill level, differences in the performance of age groups in the two classes of jobs would imply differences in the relationship of age with performance for workers in various skill levels. Ccaparisons of workers in higher and lower paid occupations can thus furnish some Information regarding the prevailing notion that the performance of skilled workers is less affected b y advancing age than is the performance of unskilled workers. Tables 3 and k show that the output indexes for female workers in both higher and lower paid jobs and for male workers in lower paid jobs in the footwear plants were substantially the same for all age groups. Hone of the indexes shown for these groups were significantly different from 10 0 , according to statistical tests which were applied. In contrast, male workers in higher paid jobs showed declines in the ^ 5 -5 ^ and 55 -6H year groups which were statistically significant. Tables 5 and 6 indicate that the index patterns for workers in both higher lower paid jobs were identical in the clothing plants surveyed. This pattern— performance b y the groups 25-5^ years which were not signifi cantly different from 100 and somewhat reduced performance b y the 55-6 k year group— follows the general pattern for men and women described above. There appears to be no consistent difference In the pattern of the age— productivity relationships between workers in higher and in lower paid occu pations. In fact, for all workers in the clothing plants and for women in the shoe plants, age did not affect the productivity of workers in higher paid jobs differently from those in lower paid jobs. It might be noted that the individual variation within age groups in these classifications did not change consistently with age. For example, the coefficients of variation for male workers in the higher paid jobs in the footwear plants declined with successive age groups, whereas the corresponding coefficients in the clothing plants increased. - 28 - Table 3 .— Indexes of output per man-hour for men pieceworkers in higher and lower paid occupations in four footwear establishments) by age group (Age group 35-44=100) Lower Higher Age group 1 / Humber of workers Coefficient of variation (percent) Index Humber of workers Index Coefficient of variation (percent) 21.9 36 96.8 10 0 .0 13.5 % J 22 3/ 105.7 17.5 12.9 3/ 2 1 3/ 1 5 .2 25-34 . 61 97.4 1 7 .8 33 35-44 . 127 10 0 .0 13.9 45-54 . 10 1 2 / 95.6 55-61* . 77 2/ 90.5 97.8 14.8 l/ Two age groups, under 25 and 65 and over, are excluded because the lumber of observations was considered insufficient. (See table 11.) 2/ This index is significantly different from 100 in the sense that, if there were really no difference between the age group and the base group, a difference as great as this would be obtained less than one time in twenty on repeated sampling. 3 / Includes lower paid machine operations only. Table 4.— Indexes of output per man-hour for women pieceworkers in higher and lower paid occupations in four footwear establishments, b y age group (Age group 35-44=100) Lower Higher Age group 1 / Humber of workers Index Coefficient of variation (percent) Humber of workers Index Coefficient of variation (percent) 25-34 • 44 100.3 1 6 .7 53 1 0 1 .1 19 .0 35-44 . 62 1 1 .1 1 1 .2 10 0 .0 16.4 45-54 . 14.2 24 83 36 98.3 55-64 . 10 0 .0 10 0 .0 96.0 102 46 101.9 1 2 .7 7.6 l/ Two age groups, under 25 and 65 and over, are excluded because the number of observations was considered insufficient. (See table 11.) 29 Table 5•— Indexes of output per man-hour for men pieceworkers in higher and lower paid occupations in four clothing establishments, by age group (Age group 35-UU*100) Higher Age grotp 1 / Ntmiber of workers Index Lower Coefficient of variation (percent) Ntmber of workers Index Coefficient of variation (percent) 25-3U..... 2/27 2 /10 0 .6 5.8 25 96.6 8.9 35-UU..... 1*9 100*0 Uu6 33 100*0 15.7 U5-5U..... 35 9 6 .2 lU. 5 16 105.1* 12.5 55-6U.... U5 3/ 93.0 18.5 65 3/ 90.3 a. 7 1/ Two age groups, under 25 and 65 and over, are excluded because the number” of observations was considered insufficient* (See table 12*) 2/ Includes higier paid machine operations only* 3 / This index is significantly different from 100 in the sense that, if there were really no difference between the age grot?) and the base group, a difference as great as this would be obtained less than one time in twentyon repeated sampling* Table 6 *— Indexes o f output per man-hour for women pieceworkers in higher and lower paid occupations in four clothing establishments, by age group (Age grotp 35-UU=100) H igher Age group 1 / Ntmber of w orkers In d ex Lower C o e ffic ie n t o f v a ria tio n (p e r c e n t ) Ntmber of workers In d e x C o e ffic ie n t o f v a ria tio n (p e r c e n t ) 25-3U.... 20 95.5 15.U 80 100.8 22.8 35—UU.•♦•. 67 100.0 12.3 153 100.0 21.8 U5-5U.... 119 96.1 15.7 268 99.2 19.2 55-6U.... 67 % / 89.9 15.3 212 % / 90.3 20.2 1/ Two age groups, under 25 and 65 and cnrer, are excluded because the ntmber of observations was considered insufficient* (See table 1 2 *) 2/ This index is significantly different from 100 in the sense that, if there” were really no difference between the age group and the base group, a difference as great as this would be obtained less than one time in twenty on repeated sampling* - 30 Consequently, v a r i a t i o n w it h in age groups a g a in m ist be viewed in terms As noted e a r l i e r , the c o n s id e ra b le degree o f v a r i a t i o n evidenced means th a t even though a d e c lin e i n av erage perform ance a f t e r age was o b se rv e d , th e re are many w orkers aged 5 5 - 6^ whose perform ance eq u ale d o r even surpassed the average perform ance o f younger gro u ps. of i t s magnitude r a t h e r than i n terms o f i t s r e la t io n s h ip t o a g e . One d i ff e r e n c e between the v a r i a t i o n w it h in age groups f o r w orkers in h ig h e r p a id jo b s and f o r w orkers i n lo w er p a id jo b s i s a p p a re n t. The v a r i a t io n w as, on the a v e ra g e , s l i g h t l y g r e a t e r among w orkers in lo w er p a id jo b s than among those in h ig h e r p a id jo b s , in d ic a t in g more in d iv id u a l d iff e r e n c e s in p r o d u c t iv it y in l e s s s k i l l e d occu p atio n s. Machine and Hand O ccu pation s. Because the nature o f machine work d i f f e r s s u b s t a n t i a lly from th a t o f handwork, d a ta a re presen ted t o shed l i g h t on the Q uestion o f whether age a f f e c t s the perform ance o f w orkers in the one type o f o p e ra tio n more than in th e o th e r. The same g e n e ra l p ic t u r e o f s t a b i l i t y u n t i l age 5^ B-Qd some d e c lin e t h e r e a f t e r i s ev id e n t in the machine-hand com parisions ( t a b l e s 7 > 8 , 9 > and 10) . There were e x c e p tio n s , however. The in dexes f o r male handworkers aged 5 5 -6H-, alth ou gh a p p a re n tly lo w er i n b o th i n d u s t r i e s , were found not t o he s i g n i f i c a n t l y d i f f e r e n t from the Indexes f o r o th er age gro u p s. A t the same tim e, the apparent in c re a s e i n the index f o r fem ale machine o p e ra to rs in the shoe p la n t s was a l s o found not t o he s t a t i s t i c a l l y s i g n i f i c a n t ( t a b l e 8 ) . One i n t e r e s t in g d iff e r e n c e between band and machine o p e ra to rs in the fo o tw e a r p la n t s should he n o ted ; the index f o r male machine o p e ra to rs aged 25 - 3^ i s s i g n i f i c a n t l y lo w er than th a t f o r the 35- ^ y e a r group. The in dexes f o r b o th male and fem ale handworkers aged 2 5 - 3 ^ a re s i g n i f i c a n t l y h ig h e r than those f o r th e co rrespon din g handworkers aged 3 5 -M -* The indexes f o r the c lo t h in g w orkers in th ese age groups were not s i g n i f i c a n t l y d i f f e r e n t from the correspon din g b a se group in dex (a c c o r d in g t o s t a t i s t i c a l t e s t s ^ f o r e i t h e r machine o r hand o p e ra tio n s . A gain no c o n s iste n t p a tt e rn evo lve d and no g e n e ra l c o n c lu sio n about d iff e r e n c e s in the a g e -p r o d u c t iv it y r e la t io n s h ip s o f machine o p e ra to rs a s c o n trasted w ith handworkers can b e drawn. The age group perform ance in dexes sh o u ld , once a g a in , be in t e r p r e t e d in the l i g h t o f the v a r i a t i o n m easures. A g a in , the range o f i n d iv id u a l v a r i a b i l i t y was s i z a b le . I n i t i a l O ccu pation al Groups. T a b le s 11 and 12 show output p e r man-hour indexes b y in d u s t ry , s e x , l e v e l o f p a y , and type o f o p e ra tio n (hand o r m ach in e). These a re the indexes o btain ed i n the i n i t i a l a g g re g a tio n o f the s p e c i f i c occupation in d e x es, and, in many c a s e s , re p re se n t o n ly a s m a ll number o f w o r k ers. B e s u its a re not shown f o r those groups c o n ta in in g fe w e r than f i v e - 31 T a b le 7 . — In d exes o f output p e r man-hour o f men p iecew o rk ers perform in g machine and hand o p e ra tio n s i n fo u r fo o tw e a r e s ta b lis h m e n ts, b y age group (A ge group 35 -4 4 =100) Hand Machine Age group 1 / Humber of w orkers In d ex C o e f fic ie n t o f v a ria tio n (p e r c e n t ) Number of w orkers 95.0 1 7 .6 30 139 10 0 .0 45-54... 113 97.5 12 .0 1 3 .8 2k 3/ 10 55-64... 93 9 1 .2 13.7 3/ 25-3*... 35-44... 64 2/ 2/ 5 In d ex 2 / 10 9 .6 10 0 .0 10 0 .2 3/ 9 8 .6 C o e f fic ie n t o f v a ria tio n (p e r c e n t ) 19.9 2 1 .0 15.3 6 .k 1/ Two age gro u p s, under 25 and 65 and o v e r, a re exclu ded because the number o f o b se rv a tio n s was c o n sid ere d i n s u f f i c i e n t . 2/ T h is index i s s i g n i f i c a n t l y d i f f e r e n t from 100 in the sense t h a t , i f th e re w ere r e a l l y no d iff e r e n c e between the age group and the ba se gro u p, a d iff e r e n c e as g r e a t as t h i s w ould b e o btain ed l e s s than one time i n twenty on rep e ated sam pling. 3/ In c lu d e s h ig h e r p a id hand o p e ra tio n s o n ly . T a b le 8 . — In d exes o f output p e r man-hour o f women p iecew orkers p erform in g machine and hand o p e ra tio n s i n fo u r fo o tw e a r e sta b lis h m e n ts, by age group (Age group 3 5 -¥<-=10 0 ) Machine Age group 1 / Number of workers 25-34... 6k 35-44.•• 45-54... 55-64... 100 97 42 Index 9 8 .8 100 «0 9 8 .0 10 3 .0 Hand Coefficient of variation (percent) Humber of workers Index 20.4 33 2/ 105.0 1 7 .0 6k 10 0 .0 1 0 1 .0 2 / 9 2 .6 13.9 32 1 1 .0 18 Coefficient of variation (percent) 9.9 9.6 9*3 1 2 .5 l / Two age gro u p s, under 25 and o ver 65 and o v e r, a re excluded because the number o f o b se rv a tio n s was co n sid ere d i n s u f f i c i e n t . 2 / T h is in dex i s s i g n i f i c a n t l y d i f f e r e n t from 100 i n the sense t h a t , i f th e re w ere r e a l l y no d iff e r e n c e between th e age group and th e ba se grou p, a d iff e r e n c e as g r e a t as t h i s w ould be o bta in ed l e s s than one time in tw enty on rep e ated sam pling. T a b le 9 . — Indexes o f output p e r B aa-h ou r o f men p iecew orkers perform in g machine and hand o p e ra tio n s i n fo u r c lo t h in g e sta b lis h m e n ts, b y age group (Age group 35-***100) Hand Machine Age group 1 / lumber of workers Coefficient of variation (percent) Index lumber of workers 17 1* .6 10 .2 *0 93.9 2 3 .0 1 5 .2 2/ 9 26 3* 15.5 TO 3/ 90.8 1 8 .* *3 35-** . . 56 *5-5* • . 55-6* . . 6.5 Coefficient of variation (percent) 2 / 10 *.* 10 0 .0 1 0 1 .6 9 6 .6 10 0 .0 10 0 .0 25-3* • • Index 9-5 1/ Two age groups, under 25 and 65 and over, are excluded because the number of observations was considered insufficient. 2/ Includes lover paid hand operations only. 3/ This index is significantly different from 100 in the sense that, if there were really no difference between the age group and the base group, a difference as great as this would be obtained less than one time in twenty on repeated sampling. Table 10.— Indexes of output per man-hour of women pieceworkers performing machine and hand operations in four clothing establishments, by age group (Age group 35-Mt-ilOO) Machine Age group l/ lumber of workers Index 25-3* . . 5* 100.3 35-** * * 129 *5-5* . . 55-6* . . 203 10 0 .0 10 0 .* 2/ 9 1 .2 106 Hand Coefficient of variation (percent) 22.7 I8 .7 1 7 .6 1 8 .1 lumber of workers Index k6 98.3 91 Coefficient of variation (percent) 2 1.9 10 0 .0 20.7 18 k 96.3 173 2 / 8 9 .2 1 8 .7 19 .6 l/ Tvo age groups, under 25 and 65 and over, are excluded because the number of observations was considered insufficient. 2/ This index is significantly different from 100 in the sense that, if there were really no difference between the age group and the base group, a difference as great as this would be obtained less than one time in twenty an repeated sampling. - 33 - T able 11. — In d ex es o f output per man-hour o f piecew orkers in fo u r footw ear e sta b lis h m e n ts, by s e x , age gro u p, and type o f occupation 1 / (Age group 35-2+l+a*100) Men Women Machine Hand Age group Number of workers In d ex Number of workers Index Machine Hand Number of workers Index Number of w orkers Index Higher p a id occupations 2 (2/) 6 92.5 3 (2/) 25-31+ ...... 22 112+.1 39 3/91+.1+ 15 lOi+,8 29 97.6 35-2+2+...... 19 100.0 108 100.0 33 100.0 29 100.0 1+5-51+ ...... 10 100.2 91 91+.8 12 101.3 32+ 99.3 55-6U ....... 5 98.6 72 3/89.1 6 3/78.7 18 106.2+ 65 and o v er • 2 (2/) 12 3/78.9 0 — 7 3/72.0 Under 25 .... 6 85.6 13 3/79.9 9 91.3 13 3/110.2+ 25-3U ...... 8 95.3 25 97.0 18 105.1 35 99.5 35-2+2+...... 5 100.0 31 100.0 31 100.0 71 100.0 2+5-51+...... 2 (2/) 22 105.7 20 100.7 63 97.2 55-62+...... 3 (2/) 21 97.8 12 101+.0 21+ 101.0 65 and over . 0 17 97.6 1 (2/) 1+ (2/) Under 25 .... 1+ (2/) Lower p a id occupations — 1/ In d ex es r e f e r to w o rk e rs ' output p e r man-hour d u rin g s e le c t e d p e rio d s o f 19 5 5 . 2/ L ess than 5 o b se rv a tio n s were con sidered i n s u f f i c i e n t f o r comparable in d e x e s . 3/ This in d ex i s s i g n i f i c a n t l y d i f f e r e n t from 100 i n the sense t h a t , i f there w ere r e a l l y no d iff e r e n c e between the age group and the base gro u p , a d iff e r e n c e as g r e a t as t h is w ould be o btain ed le s s than one time i n twenty on re p e a te d sam plin g. Table 12.— Indexes of output per man-hour of piecework ers xr four clothing establishments, by sex, age group, and type of oc rupation 1 / (Age group 35-iiUa100) Men Hand Age group Number of workers Women Machine Index Hand Number ! Index of workers Number of workers Machine Index Number of workers Index Higher paid occupations ®ader 25 .... 0 mmrnm 0 25-3U ...... 3 (£/) 27 3 5 - W i ...... 11 100.0 U5-5U ...... 6 55-6U ...... 65 and over • 1 (£/) 1 (2/) 100.6 7 89.2 13 98.0 38 100.0 12 100.0 55 100.0 95.H 29 96.U 33 3/86.3 86 100.0 8 97.6 37 3/92.0 25 3/81.1 U2 93.3 2 (2/) 16 3/80.1 0 2 (2/) 2 (2/) 5 100.6 10 96.U — — Lower paid occupations Under 25 .... 0 25-3U ...... 9 10U.U 16 3/89 . k 39 100.0 la 101.9 3 5 - U h .... . 15 10 0 .0 13 100.0 19 100.0 7h 100.0 U5-5U ...... 11 10 U .3 5 10 6 .5 151 9 8 .1 117 100.7 55-6U ...... 32 92 .U 33 3/88.h 1U8 3/ 90 .7 6U 7 89.7 6 75.6 5 3/71.3 3 65 and over • — 3/89.8 (2/) l/ Indexes refer to workers* output per man-hour during selected periods of 1955* 2/ Less than 5 observations were considered insufficient for comparable indexes. 3/ This index is significantly different from 100 in the sense that, if there were really no difference between the age group and the base group, a difference as great as this would be obtained less than one time in twenty on repeated sampling. Individuals, since it was felt that data based on such a limited number of observations would not be sufficiently reliable to be compared with indexes based on greater numbers* These tables illustrate the need for a large number of observations for each age group in specific occupations. The indexes shown in the tables reveal greater fluctuation than was evi dent in the combined indexes* 18/ This greater fluctuation is attributable, for the most part, to the small number of workers underlying each index, resulting in a greater influence on the group average of individual scores which are extreme* It should be recalled that the number of workers in any age group in each of the classifications shown in the tables (e.g*, men, aged 25-3U, in higher paid hand occupations) already is an aggregation of workers in various specific occupations in several plants* Although the initial Indexes for occupational groups appear to fluctuate more than those for the combined occupational groups, they nevertheless exhibit similar patterns* For the most part, there were no significant differences between the indexes for the age groups 25-5U; after age 5U, a snail decline, statistically significant, occurred* While the varying composition of these combined groups will not inpair the comparability of the different age groups within a series (since the same weights were applied in combining each of the age groups in the series), it will affect the comparability of one series with another* To whatever extent the relationships between age and work performance differ among the occupational groups, the comparability of indexes representing combinations of these groups will be impaired* Attendance Data on attendance were collected for U,009 production workers of which 1,758 were in the footwear plants and 2,251 were in the clothing plants* Although the attendance indexes show minor differences between age groups, as indicated in tables 13 and lU, these differences are of such limited magni tude as to justify the conclusion that attendance rates in the plants surveyed show no appreciable relationship with age* In the clothing plants, the indexes of all age groups fell within 95*5 and 102*3 percent of base group average* In the footwear plants, the range was even smaller— 98*7 to 101*6* W ith re g a rd to in d i v i d u a l d i ff e r e n c e s , the in d iv id u a l attendance r a t e s w it h in comparison groups showed rem arkable co n siste n c y and i t became e v id e n t, a t an e a r ly s t a g e , th a t no purpose c o u ld be served b y c a lc u la t in g the co e f f i c i e n t s o f v a r ia t io n o f th ese r a t e s * The in d iv id u a l d iff e r e n c e s about the a v e rage in d e x es were so sm all th a t th ey p la y e d no r o l e in the com parisons* 18/ Cf* tables 1 through 10* Table 13-— Indexes of attendance of pieceworkers in four footwear establishments, by sex and age group 1 j (Age group 35-MnlOO) Women Hen Age group Number of workers Index Number of workers Index 65 99.7 129 1 0 1 .2 1 0 1 .6 159 3 5 - ^ ................. 197 10 0 .0 259 10 0 .2 10 0 .0 *5-5* ................. 55-61*.................. 190 18 3 101.3 230 100.3 10 0 .8 127 100.9 83 98.7 32 100.5 Under 25 ............... lX)h 25-3* ................. 65 and over .......... 1/ Indexes refer to workers’ attendance during selected periods of 1955* Table ll*.— Indexes of attendance of pieceworkers in four clothing establishments, by sex and age group 1 / (Age group 35 -kkrioo) Hen Age group Women Number of workers Number of workers Index 22 2 / 10 0 .8 65 102.3 ................. 127 99-7 lkl 3 5 - H ................. 153 305 ^5-5^ 112 263 10 0 .0 10 0 .i* 10 0 .6 10 0 .0 560 99-2 98.5 1*25 99.5 Under 25 ............... 25-3^ ................. 5 5 - 6 ^ ............... . 65 and over .......... 2/ Index 1 0 1 .1 59 2/15 2/ 95.5 1/ Indexes refer to workers’ attendance during selected periods of 1955. 2 j Includes lower paid occupations only. 37 - Table 1 5 •— Indexes of attendance for pieceworkers in higher and lower paid occupations in four footwear establishments, by sex and age group 1/ {Age group 35-UU=100)__________________________ Ken Age group Higher Number Index of workers Women Lower Number Index of workers Higher Number Index of workers Lower Number Index of workers Under 25*•• 21 100.5 83 102.0 13 103.6 52 98.0 25-3U..... 68 100,3 61 103.0 63 100.6 96 100.0 35-UU..... 135 100.0 62 100.0 8U 100.0 175 100.0 U5-5U..... 119 100.5 71 102.1 73 101.1 157 99.9 55-6U#*..*. 97 99.7 86 101.9 3U 101.7 93 100.6 65 and over 20 97.5 63 99.9 5 102.6 27 99.6 1/ Indexes refer to workers* attendance during selected periods of 1955. Table 16.— Indexes of attendance for pieceworkers in higher and lower paid occupations in four clothing establishments, by sex and age group 1/ Women Men Age group Higher Number of workers Index Higher Lower Number of workers Index Number of workers Lower Index Number. of workers Index Under 25... 2 (2/) 22 100.8 16 102.9 U9 102.0 25-3U...... 63 100.0 6h 99.1; 38 101.7 103 100.1 35"*Ubo*«*.» 93 100.0 60 100.0 103 100.0 202 100.0 U5-5U...... 67 100.2 H5 100.6 203 101.0 357 98.U 55-6U..... 131 98.7 132 98.2 llU 101.0 311 98.8 27 101.5 32 100.6 2 (2/) 15 95.5 65 and over 1/ Indexes refer to workers* attendaice during selected periods of 1955* 7 / Less than 5 observations were considered insufficiently reliable for comparison of indexes. 38 As can be noted in tables 15 and l6, no consistent differences in the patterns of the age group indexes can be observed for higher and lower paid occupations. Industrial Injuries Data on industrial injuries were collected for 2,637 workers, of whom 729 were in footwear plants and 1,908 in clothing plants* Tables 17, 18, and 19 illustrate the nature of the plant data which could be obtained in the surrey. In many age groups, no injuries were recorded. It is evident that a larger number of individuals, or a longer period of observation, is required to derive any meaningful data on injuries. As noted previously, the index method was not used here. In several categories, no base group was available (since no injuries were recorded in the base group). A word of caution is appropriate concerning even the limited data shown in tables 17, 18, and 19 . Due to the variability of reporting practices among the plants, particularly as regards nondisabling injuries, the injury experience of any one plant will not be comparable with that of another. Note, for example, that plant B reported 5^5 nondisabling injuries, whereas plant C, which was of approximately the same size, reported only h j . This difference undoubtedly reflects the absence of uniform recordkeeping practices. Separations The separations data shown in tables 20 and 21 are illustrative of the type of information that can be obtained in a small-scale survey, and indicate some of the difficulties involved in the collection of separations rates. Records of separations were kept in detail at only ^ plants providing figures for 2,73^ workers over the period of a year or more. Although actual con clusions relating to the separation rates of various age groups are difficult to derive from the findings, certain aspects of the technical problems encoun tered in this field are pointed up quite clearly. There are two noteworthy characteristics in the data shown in these tables. First, the indexes cover a remarkably wide range— from 0 to 879 .2 . Secondly, the number of separations occurring in each age group is extremely small, with many groups showing no separations at all. It is evident that these data are of limited value, insofar as any possible generalizations are concerned. The problem here is somewhat similar to that with respect to the industrial injury findings, in that a longer observation period, or a larger number of individuals, would be necessary to produce any definitive results. Within these limitations, however, the indexes appear to show tendencies which correspond to those which might be expected. In the clothing plants, - 39 Table 17.— Industrial injuries of pieceworkers in selected shoe plant A by sex, occupation, and age group, during 1-year period ending December 31, 1955 Men Occupation and age group Nuufcer of workers Women Number Exposure of non hours disabling injuries Humber of dis abling injuries Number Exposure of hours workers Number of non disabling injuries Number of dis abling injuries Hand occupations Uhder 25 ......... 10 17,631+ 3 0 6 10,581+ 1 0 25-31+ ............ 3 5,503 3 0 25 l+i+,818 2 0 35-1+1+........... 5 8,267 0 0 55 103,917 6 1 1+5-51+ ............ 2 3,81+5 0 0 35 65,766 2 0 55-61+ ........... 9 15,138 0 0 12 23,01+2 0 0 1 2,159 0 0 65 and over ...... — — — — Machine occupations Under 25 lii 23,921+ 2 1 10 17,583 0 0 25-31+ ........... 27 1+9,792 2 1 1+8 87,910 2 0 35-1+1+........... 82 11+8,151+ 8 0 83 151,1+57 11 1 1+5-51+............. 97 175,037 2 1 101 186,955 6 0 55-61+ ............ 59 110,251+ 6 2 39 72,077 3 0 7,201+ 0 0 2 3,695 0 0 65 and over ...... 1+ Table 18. — Industrial injuries of pieceworkers in selected clothing plant B by sex, occupation, and age group, during 2-year period ending December 31, 1955 Men Occupation and age group Women Number Number Exposure of non of disabling hours workers injuries Ndniber of dis abling injuries Nunber Exposure of hours workers Number of non disabling injuries Number of dis abling injuries Hand occupations Under 25 ......... 1* 11,532 11 0 10 26,368 7 1 25-31*............ 5 17,306 2 0 21* 71,012 6 0 35-1*1*............ 15 1*5,271* 11 0 57 173,009 32 0 1*5-51* ............. 16 1*8,21*2 7 1 118 358,513 1*3 3 55-61*............ 1*1 132,675 9 1 127 396,052 36 1* 65 and o v e r .... . 3 8,620 0 0 3 10,1*68 0 0 Under 25 ......... 6 16,1*79 7 0 10 26,751 21 0 25-3U ............ 22 67,882 11* 0 15 1*1*,267 U* 0 35-1*1*............ 26 91,803 16 0 71* 226,860 52 0 1*5-51*............ 21* 81,951 17 1 188 567,817 153 8 55-61*............ 36 116,902 20 2 110 326,029 66 3 65 and over ...... 7 21,311 1 0 2 5,567 Machine occupations 0 0 Table 19,— industrial injuries of pieceworkers, in selected clothing plant C by sex, occupation# and age group, during 2-year period ending December 31, 195? Men Occupation and age group Number of workers Women Number Exposure of non disabling hours injuries Number of dis abling injuries Number Exposure of hours workers Number of non disabling injuries lJumber of dis abling injuries Hand occupations 2 8,000 0 0 10 28,1*00 0 0 25-31* ............. 22 78,500 0 0 21 61*,600 1 3 35-U* ............. 22 82,600 1 1 66 185,600 1* 3 1*5-51* ............ 20 75,1*00 0 1 108 327,1*00 6 3 55-61* ............. m 157,300 2 3 122 389,800 6 1* 6 23,200 0 0 7 17,300 2 0 Under 25 ......... 13 35,700 0 0 15 36,600 0 0 25-31* ............ 36 122,200 2 1 1*1* 131*, 700 3 1 35-1*1+............. U1 11*7,800 1 0 91 285,800 6 2 1*5-51* ............. la 11*9,000 1 1 131* 1*27,700 9 7 55-61* ............ 29 108,000 0 0 60 19 0 ,50 0 3 1 65 and over ••••«•• 5 17,700 0 0 9 29,000 0 0 Itader 2 ? ......... 65 and o v e r .... . Machine occupations the under 25 age group shows a very high rate of separatists, at does the 65 and over group, whereas the li5-5^4 and 55-6i4 year groups show an extremely low rate of separations reflecting the relative stability of these groups. The youngest age group is generally recognized to be one of greater mobility, while the 65 and over class reflects the high incidence of retirements. The intermediate groups show rates that vary considerably. These rates are, in general, lower than the rates for the youngest and the oldest groups. In view of the inadequate data, it is not possible to identify any sig nificant differences in the age-separations patterns shown by the various groups. In a larger scale survey, however, it would probably be important to retain the categories used here, in which distinctions are made according to sex, industry, and length of service. Table 20.--Indexes of separation rates of pieceworkers in two footwear plants by sex, length of service, and age group (Age group 35-Mi“100) Men Length of service and age group Women Number Number Number of of sepa of workers man-months rations Index dumber Number Number of of of sepa workers man-months rations Index Less than 2 years’ service I tr under 25 .............. 52 509 18 (V) 23 21*1 8 636.0 25-3U ................. 8 81 3 (1/) 27 269 5 387.8 35-UU ................. 5 Uo 2 (V) 38 396 2 100.0 U5-5U ................. k 33 1 (V) 17 158 0 0 55-6U ................. 1 7 0 (l/) 2 lit 0 (1/) tr I 65 and over ........... — m m m m — — — ~ — — More than 2 years' service Under 25 ••..... ...... 32 309 5 70U .0 35 365 8 879.2 25-3U ................. 79 708 U 3b2.1 116 1,202 7 21*6.2 3 5 - M i ................. 23k 1,388 3 100.0 180 1,975 5 100.0 U 5 - 5 4 .... ............ no 1,270 U 163.6 173 1,916 k 81.U 55-6U ................. 95 1,030 U 183.5 73 806 6 285.U 65 and over 10 90 1 693.9 5 50 0 0 1/ Less than 5 workers or less than 50 man-months in the base group or age group were con sidered insufficient to permit reliable indexes. Also, indexes were not calculated for those series in which the base group showed no separations. Table 21.— indexes of separation rates of pieceworkers in two men's clothing plants by sex, length of service, and age group (Age group 35-l*U=100) Men Length of service and age group Number Number of of workers man-months Women Number of sepa rations Index Number Number Number of sepa of of workers man-months rations Index Less than 2 years' service Under 2 5 ....... . 20 200 7 (1/) 21* 321* 6 89.7 25-31*............... H* 31*0 2 (1/) 26 288 3.5 121.5 35-1*1*............... 8 80 0 (1/) 1*5 506 13 100.0 1*5-51*............... 6 60 0 (V) 27 281* 9 108.7 55-61*................ 2 3U 0 (1/) 13 130 1* 109.2 6$ 1 21* 0 (1/) 1 10 0 0/) Under 25 ............. 13 186 2 262.2 19 316 9 615.7 25-31*............... 1*1* 1*96 5 31*7.5 73 1,290 31* 2l*l*.6 35-1*1*............ . 66 758 5 100.0 157 2,298 10 100.0 U5-5U ............... 82 988 2 33.7 369 1*,768 16 63.1* 166 1,758 7 1*1*.5 280 3,276 16 89.7 35 350 9 303.1* 21* 380 15 835.8 and over More than 2 years' service 55-61*................ 65 and o v e r ...... . 1/ Less than 5 workers or less than SO man-months in the base group or age group were con sidered insufficient to permit reliable indexes. Also, indexes were not calculated for those series in which the base group showed no separations. Appendix I. Farther Notes on Statistical Methods This section is included in order to clarify the assumptions underlying the statistical methods adopted, and to describe more folly the steps followed in deriving the measures of work performance. It is not included in the body of the report, since it is believed to be of limited interest to many readers. As indicated throughout this report, there were two basic problems to be resolved by the statistical methods applied in this investigation. First, it was necessary to derive comparisons which isolated the influence of age from the many other (and often more important) factors which act upon a person's work performance. Second, there was the problem of combining the measures drawn from small groups of persons, which alone could not furnish meaningful results, into larger aggregates from which statistical conclusions might be drawn. The firs t problem was resolved in two ways—classification of workers and the use of relative scores. The second problem was resolved, to a certain extent, by applying the appropriate weights to the groups to be combined. For each of the performance indicators the specific classification scheme varied, as did the weights applied to the measure, but the fundamental approach was similar. Before discussing the bases for the statistical methods applied, it would perhaps be useful to indicate briefly the definition of the universe which is being measured by this investigation. Definition of Universe As noted previously, the findings resulting from this study are appli cable only to the particular plants included, and do not necessarily reflect conditions throughout the two industries. In another sense, however, the individual employees for idiom data were collected constitute a sample drawn from a larger population. I f a different survey period had been selected, or i f the eight companies had employed individuals other than those whose characteristics were recorded in this study, the results would, of course, have been somewhat different from those reported here. The data presented in this study are, with respect to the particular individuals concerned, actual measurements rather than estimates. However, these individuals may be regarded as a sample, drawn from a universe which includes all possible employees who might be found, at any time, to be working in plants which are identical to the ones studied in matters affecting employ ment practices and working conditions. I f this broader applicability is ascribed to the findings, then they must be regarded as merely estimates, and subject to certain errors. - k 6 - Methods for evaluating the reliability of these estimates--that is, of determining the probability that the estimates w ill fa ll within a specified percentage of the results that would have been obtained i f the entire universe had been used rather than a sample—are available through the application of appropriate statistical techniques. It was this interpretation of the popu lation which led to the use of reliability weights which are discussed later. Occupational Classification Direct comparisons of output per man-hour scores were made only among individuals in the same specific occupation. The occupations were, in turn, classified into several occupational groups according to the following charac teristics: hand operations, machine operations, higher paying jobs, and lower paying jobs. For attendance, direct comparisons were made among individuals whose occupations were in the same earnings classification. Earnings Classifications. The idea behind the classification of workers according to the average earnings of their occupations is that earnings, on the whole, can be regarded as indicative of the relative degree of sk ill and experience required for the job. Special exceptions, of course, have to be made for jobs in which the level of pay is relatively high for other reasons, such as less desirable working conditions. Initia lly, an attempt was made to classify jobs into skilled, semiskilled, and unskilled occupations according to classifications given by the Dictionary of Occupational Titles. 19/ After this had been done, it was found that many sk ill level classifications thus derived were inconsistent with the average earnings of persons on the job. Some "unskilled" jobs were among the highest paid occupations, while some "skilled" jobs were in the lowest paid group. This was probably because of the great variation in the nature of jobs which carry the same title in different plants. Because of these inconsistencies, it was decided that average hourly earnings for jobs would provide a better basis for classification. There are several alternatives which could have been used for establishing the lim it to divide jobs into higher and lower paid groups. One is to draw a dividing line for each plant surveyed} another is to establish a regional lim it. The use of plant averages would reflect special differences in condi tions which affect earnings in particular plants, such as plant efficiency, degree of unionization, and local bargaining power of particular groups of workers. For purposes of this study, however, some criterion was desired which would be sensitive to the actual sk ill levels of workers, rather than their status in relation to the rest of the workers in the plant. Such a criterion 19/ Dictionary of Occupational Titles, Federal Security Agency, U. S. Employment Service, Division of Occupational Analysis, March 19U9• - U7 - was necessary in order to arrive at some grouping of sk ill levels which would be consistent from plant to plant, and would thus permit the aggregation of indexes from various plants according to a sk ill level classification. A specific dollar figure was established, therefore, for each industry within a given region, and was used to distinguish between higher and lower paid occupations. 'This figure was derived from the average hourly earnings for the specific industry and region (as determined through wage surveys conducted by the Bureau 20/) adjusted for changes in wage levels since the date of the most recent survey. This figure was then used to classify each of the occupations found in the present survey. Those occupations in which the average hourly earnings (within a given plant) exceeded the regional average for the industry were considered higher paid, whereas those in which average earnings fe ll below this figure were considered lower paid. This was done separately for male and female workers. In this way, the sk ill level classification which was assigned to each occupation depended on the relationship of the average earnings in that occu pation to the overall regional average for the industry, rather than to the average for the one plant alone. It was believed that the use of regional industry averages as cutoff points would provide more reliable indications of actual sk ill requirements than would the use of individual plant averages. Machine-Hand Classifications. The machine-hand distinctions were made in order to separate jobs which place somewhat different requirements on workers. Machine jobs, it is believed, call for many sk ills and talents different from those needed for hand operations, and the sk ills peculiar to machine operations or to hand operations influence the productivity of various age groups differently. By making this distinction, the influence of these factors in the age group comparisons was minimized. A machine job was somewhat arbitrarily designated as one which required the use of a powered device. Most of the designations were arrived at after a discussion with plant officials as to the particular equipment used in the various occupations. In some cases, where it was difficult to classify the job, the judgment of the plant official who was aware of the physical require ments of the job was used. 20/ Wage Structure - Footwear March 1953, BLS Report U6, December 1953♦ Men's and Boys' Suit and Coat Industry: Earnings March 195l> Monthly Labor Review, November 1951 (pp. 573-575)* 1*8 Transforming Absolute Scores Into Indexes As stated earlier, in the case of output per man-hour, the average hourly earnings of the age groups in a specific occupation were related to the aver age hourly earnings for the 35-hk year groip, which was used as a base. In the actual derivation, 2 different 10-year age groups were chosen as bases of comparison, the group 35-UU designated base group "A" and the groip 2$-3k called base group "B" « Indexes could be constructed only for those operations where workers of base group age were present* The use of 2 base groups instead of 1 permitted the inclusion of additional occupations in the productivity comparisons* In this way a greater proportion of the raw data collected during the plant visits could be utilized* 21/ In those occupations which included persons in both base groups, two productivity indexes were derived for each age group* A single 20-year base group, ages 25-UU, was considered and rejected because, on aggregating over occupations, the results might reflect differences in performance associated with the average age of members of the base groip, rather than differences in the performance of the age groups compared. Combining Occupation Indexes The occupation indexes of an age group using age group 35-UU as a base (base group A) were combined with appropriate weights to furnish an occupational group index for that age groip* The specific occupations are viewed as samples yielding estimates of the index for the occupational group* They should, therefore, be combined, using weights which take proper account of their re lia b ility. The occupation indexes were usually based on different numbers of people in the age group and different numbers of people in the base group. Accordingly, they are more reliable the greater the number of individuals in the age group and the greater nwber of individuals in the base group* The formula for the weights was NaNb/Wa+Nb 'diere Na is the number of individuals in the age group and Nt is the number of individuals in the base group* 22/ 23/ 2 1 / Be *-ause of the limited data available-in some cases there were no individuals in some age groups—statistical techniques such as pairing or standardization procedures could not be applied to productivity comparisons by age groups* These techniques require equalizing the occupational composition of each group or giving results from each occupation the same weight in order to make the age groups comparable* To apply these procedures, at least 1 person from each of the 6 age groups must be present in each occupation* 22/ The derivation of this formula was worked out with the assistance of the Bureau's Office of Statistical Standards* Each weight should be inversely proportional to the variance of the index to which it applies* 23/ For attendance the same form of weights was applied in combining the earnings level classifications in each plant* One modification was that the weight had to be multiplied by the number of scheduled workdays in the plant during the survey period* A similar procedure was employed in combining the occupation indexes based on age group B. Thus, for each age group, two indexes were derived for the same occupational group. The final step in deriving the index for the occupational grouping is to combine the indexes based on groups A and B. To do this, the B indexes for all age groups were shifted to group A through dividing them by the B index for age group A (35-UO• This converted a ll indexes into series based on a score of 100 for base group A. The two series were then averaged by means of weights expressing the reliability of each index. Measures of Dispersion The basic measure of dispersion in an age group was the coefficient of variation for the specific occupation. I t did not matter whether the coef ficient was determined from the raw scores or the indexes for the individuals, because, within an occupation and age group, each raw score is divided by a constant to derive the index for the occupation. The dispersion measures for the occupational groupings were derived by combining the measures for the occupations. These were actually derived by combining the squares of the coefficients of variation with appropriate weights and then taking the square root. In this case, also, the number of independent observations in each age group determined the reliability and was used as the weight. The number of observations in the base group has no in fluence since it does not affect the value of the coefficient of variation within an occupation. 2h/ Measures of relative dispersion for individual attendance rates in the age groups are not presented in this report. I t was fe lt that the measures would possibly be misleading, should inferences be drawn. The distributions of individual attendance rates are highly skewed with the mode very close to the maximum score of 1 0 0 , a very short ta il to the right of the mode, and a long ta il dropping sharply to the le ft of the mode. Statistical Significance Testing Procedures were employed for testing for statistical significance the differences between the age group indexes. Each age group index for an occupational group and combinations of these groups was compared with the corresponding base group index of 100. The standard error of the difference 2k/ The number of independent observations is one less than the number of persons in the occupation. 50 between the two indexes was obtained and its standard r > re cor,, nrtea. I f the probability is less than 5 percent that the difference of a given size or larger would occur by chance* assuming the two indexes are the same* the difference was considered significant. £5 / It was similarly possible to test the significance of the difference between any two age group indexes within an occupational group or between such groups. 26 / 25/ It might be noted that* since the base group index of 100 is an exact number and not an estimate, it has no standard error and the standard error of the difference between the two indexes is the standard error of the age group index alone. 26/ In this case the variance of the difference between the indexes is the sum of the variances of the two indexes assuming no correlation between the observations making up the two indexes and the standard error is the square root of that variance. This assumption is not correct for age group indexes in the same occupational grouping. These indexes are in part composed of the same base groups and are, therefore, partially correlated. Wherever this is true the assumption makes the computed standard error larger than the correct one. Here, a difference which is found significant at the 5-percent level, on the basis of its computed standard error, w ill actually be signif icant at a level of less than 5 percent. 51 II# Derivation of Formulas 1# Weights for Combining Indexes for Specific Occupations The output per man-hour Indexes were combined to furnish an Index for an occupational group. Here, there are a series of indexes of the form where and are the average hourly earnings of a sample of Nc^ individuals in age group Cand in the base group for occupation i, respectively# In order to obtain from the specific occu pation samples an occupational group index having the minimum variance, each sample index should be weighted according to its reliability, i.e. according to the reciprocal of the squared standard error of the sample index# I f the numerator and denominator samples are uncorrelated, then the rel-variance of each age group index for a specific occupation is V2 (Ici) ¥ where Vc2 and V^2 are the population rel-variances of the individual scores in the age and base groups respectively. Another form of V2 (Ici) is: NCi+ Nbi) v 2d c i ) ~ Setting Wi ><bi»cl Nbi Nci 7 2 !l , Mc i + 52 " m then 7 < 2 v2 (Ici) * 55 - i 2 but v2 (Ic^) „ where I c is the population index for age group c T 2 and 0 -2 (1 ^) is the variance of the sample index. Using the reciprocal of the variance of each occupation sample index as the weight, then the index for an occupational group is: W i Lc i & C . V , <5-2 ( I c i ) c xc 2 j 2 I ci W i ^ o-2 (Ici) £ Vc2 Ic2 Since 7c2 and I c2 are constant with respect to the summation wbi Nci I ci !£ , Ncl+ Hbi v T c -* wl Tci £ Wi « b z i « d Tb2 „ " — j N c i+ ^ b i I f the assumption is made that the rel-variances of the age groups 2 2 NbiNci are the same, i.e . V v « 7C , then --------- . 27/ Nbi+Nci ~ 27/ There was little evidence in the findings to challenge the assumption that 7C^ ■ 7b2. The differences between the age group coefficients of variation were not consistent nor, for the most part, sizeable. In fact, age groups which had the largest nmber of observations (and hence the most reliable estimates) had almost the same coefficients. I t should also be noted that any difference between 7b2 and 7C2 would have little effect on the relative weights used for averaging the occupation indexes. 53 2* Variance of an Age Group index for an Occupational Group The occupational group index Y c for age group C is 6 and the variance o f Y c la < r 2 (T c > A s shown above, ,J ‘ 2 ( I c l K <r-2(ici) . V C2IC2 W i Therefore, 3* <f*2 (Yc) . ^ V° 2 Weights for Combining Indexes to base A with Indexes to base B As noted above, 2 series of Indexes were computed from occu pational data, 1 to base group A (35-UU) and another to base group 6 (25-3U)* Each series of Indexes was averaged separately into an occu pational group index* The series of age group indexes to base B was £®/ In this derivation, use is made of the principles that (a) the variance of a sum of unco rrelated variables is the sum of the variances of the variables, and (b) the variance of a variable times a constant is the square of the constant times the variance of the variable* converted to base A by dividing each B index by the index of age group A based on group B. a ’lc ■ This led to a series of converted indexes of the form where the left hand subscript denotes the base used and b*a a ’ represents the converted B base index. For each age group, the index aIc verted index a tlc was then averaged with the con b y means of reliability weights, i.e. a Ic f c r - ^ (a I c ) J + a ' I c t « r z ( a 'I c ) J a . a '^ c 1 ^ 1 (aIc) cr-2(aI c) = 3 fl1! - • £ a w ci From above, tf^Ca'Ic) is derived as follows: V2( a. I c) S 'V 2( „ I C) + T 2( „ I a) « V2(b lc ) + T 2(bI a) . ipV (bI c)V (bI a) 29/ From the formula for the variance of an occupational group index, it is known that i b wd therefore t2 ac ^ c _i_ *a tryir 29/ Although there is some correlation between indexes ^Ig and \>Ia, the influence on the relative weights is very small when the correlation tern is dropped. *• 55 - Again assuming that v£ « v| , , whence The average index combining the two estimates for each age group is 4- aIc 2 a Wc lu a'*c ^ - a ,wc + / a » Wc Variance of the Combined Index The variance of the combined index (a>atlc) can 1)6 fotnd b y the same procedure as described in (2) above* The variance of this index is needed to conduct tests of significance on the differences between the age group indexes* - 56 - The variance for an occupational group index as derived in (2) involved no correlation between the Indexes for the specific occupations. In this case, however, some correlation exists between the two indexes for each age group— the A based index and the converted B based index. Both indexes for an age group are derived in part from the same specific occupation sample. For these particular occupations, though the base group components involved different individuals, the age group components are based on the average hourly earnings for the same individuals. Be cause of the complicated form involved when this possible correlation is introduced, an approximation procedure was employed. The combined Index should be at least as reliable as one of its component indexes. If the correlation were perfect then no reliability would be gained by combining aIc and a iIc . As a limiting case, therefore, the reliability of the combined index is equal to the more reliable of its component indexes. Accordingly, the variance computed for the occupational group index to base A, aIc, was used to approximate the variance of the combined ^2 t index, a, •xc. The variance was ■ c t t 2 a c aw ci The standard error computed on this basis is generally larger than the true standard error of the combined index. Thus, any difference in age group indexes which are found significant at a given probability level through this procedure would actually be significant with even greater probability. - 57 - 5* Coefficient of Variation for an Occupational Group The age group coefficient of variation for an occupation group was derived by combining the rel-variances of specific occupation samples and taking the square root of this average rel-variance. This section explains how the weights were applied to obtain the average rel-variance. For an age group in a specific occupation let Ni - the number of individuals in occupation i (must be^ 2) X-^ = mean of the sample Y i = mean of the population in the specific occupation* This value is estimated by the sample mean o » _1 N < - which is an estimate of the population 1 variance - 2 j£(X-t <f2 S * / x * , the rel-variance of the sample, an estimate of the population rel-variance V2 = . Assuming a normal distribution in the specific occupation, the relvariance of 2 is — K v 20 $ sx ~ — , 2 and the rel-variance of X. is a i 2 . i£ 1 i - 1 2 according to a general rule for the rel-variance of a square* t N, 58 o — 2 '? If S| and X i are uncorrela ted, the rel-variance of ^ - 2V2 2Ll±2V?ir_ is a, proxiraately 1 N i(l+-2V2)J ' 3? 2(1 2V2 ) since the second term of the bracketed expression will be less than 0.08 provided V < 0*3 and than 0.12 provided V < O.ii and 2 So the variance of n£2 and less n £ 2. is approximately 2vW 1 A - A/tj ■— , where W^= N^-l. The estimate of the rel-variance for an occupational group is therefore and its estimated variance is i W S) 2vari“c* = 4 * 6. . Combining Occupational Group Indexes As noted above, occupational group indexes for an age group were combined with weights equal to the total number of workers of all ages in the particular occupational group, i.e. - “ £ (* * 1 ) a . a '^ c £ Mi - 59 - Where Ic s. major grouping index (hand, machine, etc*) for age group C Mj - number of workers of all ages in occupational group i<> The variance of this index, following the same procedure outlined in (2) is (iM i)2 j 2 where vc •lc Ic) ^ a,a,Wi - 60 - UNITED STATES DEPARTMENT OF LABOR Bureau of Labor Statistics Washington 25, D. C. CONFIDENTIAL Age and Work Performance _____________ Industry _____________ I Plant ______________ Address Parent Company A ddress Officials interviewed* (Cross out, "Co." or "Plant") Name______________________________________ Title__________________(Co.) (Plant) Name______________________________________ Title__________________(Co.) (Plant) Survey made ty Dates _________________________________________________Dates___________ The data submitted on this schedule will be seen only by sworn employees of the Bureau of Labor Statistics. The data will not be released in any form which permits identification with any specific company, without written permission. A. General Information 1. What are the principal products manufactured in this plant and their price range?__________________________________________________________ 2. During normal production periods approximately how many production workers are employed?____________________ THE FOLLOWING QUESTIONS REFER TO PRODUCTION WORKERS ONLY B. 3o Plant Records For what periods during the first half of 1955 was this plant operating on a full production schedule? (If these periods vary by department, spe cify )__________________________________________________________________ 61 U. For what departments do you maintain records which will yield data on output per man? 5. Briefly describe these records 6* Which of the following are factors in determining piece rates: Yes r a* Time studies b. Employee - management conference c« Other (specify) j Yes / no e j / No / / 7o Are time standards available for piece rate jobs Yes / / No / /, and other jobs (specify)?_____________________________________________________ 8. When were the piece rates last reviewed? And approximately what percentage of piece rate jobs was covered by this review? 9. For what piece rate jobs have maximnn production limits been established (limits such as maximum number of units paid for per hour)? 10* Do you maintain records of work injuries on workmen's compensation forms / 7 or otter forms? Specify 11. Do you maintain a record of total working hours for each employee ty quarter / A year f~ /, or other period? 12. During slack periods, is seniority a factor in determining the order of employee production layoffs? Yes / J No / / 13* Do you maintain special records of employee absences? ill. If yes, describe 15. For employees who have left during the past year, do you record the date on which they left Yes / '*/ No / /, and the reason (quit, lack of work, etc.)? Yes f 7 No E j 16. After how many weeks of absence will an employee be marked as separated on your records?______________________ 62 Yes f~ ~j No Z = 7 17* Do your records contain any information on the quality of work turned out by individual workers (such as number of rejects, quality warnings, etc.)? Yes [~ ~ J No / / If yes, describe_____________________________ C. Placement Procedures Do your procedures for placing production workers include the following: 18. Initial physical examination Yes / / No Z = 7 19. Periodic physical examination Yes / / No / / If yes, give time interval between physical checkups 20. Aptitude testing Yes /" 7 21. Analysis of physical job requirements: No / / a. Written description of physical requirements (such as w orking position, physical exertion, vision, etc.) Yes f ~ / No / / b. Informal evaluation Yes r j No r j 22. Other, specify_________ 23. What program is there for the retraining and reassignment of production workers? 2lu What has been done to retrain and reassign older workers?_______________ 2$. Have any measures b een taken to review and redesign jobs held by older workers? Yes / / No / /. If yes, give example, and if possible indicate reasons for initiating these measures___________________________ D. Data for Adjusting Performance Measures 26. Overtime rates become effective after 27. What is the premium rate for overtime work 28. If these rates of extra pay do not apply to piece work, specify the premium rates on piece work for overtime and holidays_______________ 29* Dates of vacation periods of plant_______________________________________ 63 hours per day, hours per week. , Sunday or holiday work___ Age and Work Performance General Instructions for Completing Questionnaire The questionnaire and worksheets on "Age and Work Performance" are to be used to collect data pertaining to productivity, absenteeism, and work injuries of individual production workers in the plants studied. These data are to be collected together with employee1s ages and other pertinent personal information. The questionnaire relates to general information, plant records, placement procedures and data-adjustments (sections A through D). Worksheet 1 is used for recording personal information, data on production, absenteeism and injury for each worker} a supplementary worksheet 2 is to record detailed productivity information where necessary. The recommended procedure is to fill out the questionnaire during the initial interview with the plant official, and then to record the individual employee data car the worksheets. Questionnaire Instructions are included only for those items not considered selfexplanatory. If additional space is needed for answers, use back of sheets. 1. Principal products — Indicate principal products manufactured in terms of broad product classes, such as Men’s Goodyear Welt Shoes, Mai’s Suits. Designate price range at retail prices for an indication of general quality range of the plant’s production. 2. Employment — Enter approximate number of production and related workers in this plant. These include workers (up through the working foreman level) engaged in fabricating, processing, assembling, inspection, re ceiving, storage, handling, packing, warehousing, shipping (but not de livery), maintenance, repair, janitorial, watchman services, product development, auxiliary production for plant's own use, recordkeeping and other services closely associated with these production operations. If the plant has less than 500 workers, record this information and terminate the interview. 3* Production Period — Obtain dates for 8 weeks (not necessarily consecutive) when plant was operating at full production. U,5» Output Per Man Records — Payroll records which yield straight piecework earnings of production workers separate from timework earnings will furnish output per man figures. - 6U - If such payroll records are not available, production records from which individual straight-time piecework earnings can be derived are satisfactory. Straight-time piecework earnings can be computed from records which show the quantities produced at given piece rates by indi vidual workers. In some cases output data may be recorded also for tiraeworkers. Inquire whether these data are available. 6, 7, 8. Piece Rates — The purpose of these questions is to ascertain whether piece rates reflect accurately differences in the time re quired to perform the same operation cm different models. If they do, workers performing the same operation can be compared regardless of differences in their product mix. 13, 1U. Absenteeism Records — Indicate whether any special records main tained by the establishment will furnish information on time scheduled and time Marked. Scheduled days and days worked may have to b e obtained from timecards directly. Determine whether timecards of piece-rate workers are available for full production periods of at least 8 weeks, preferably during the first half of 1955* 16. Ascertain what the plant practice is. 17. Describe nature and location of such records. 22. Other Placement Procedures — Indicate any steps not mentioned above which are enployed in placing production workers. 23. Retraining and Reassignment — Use retraining as teaching the worker to perform a new set of operations, or to modify his present set of opera tions. Use reassigiment as the transfer of the worker to another occu pation (set of operations). Reassignment does not necessarily involve retraining. 26, 27. 29. Preraira Rates — If the premium rates vary by job classification, list them on back of the sheet. Vacation Periods — If vacation periods vaiy by department, list the departments and relevant periods. - 65 - Name o f P la n t Clock No. 3PE Occupation D e s c r ip tio n : OPE TH * T" .u . I 1 .u . i i “ r* 1 i i L .J L Date D isabled I r“ Days D isa b led AS C P Date Rate PS H 1 PPS Q S M 2 DWS DWS -t— •L. i i Date H ired Y ears S e r v ic e X Date Returned IS H ourly Ending -c~ t Date Born I I T “ . . . Date In ju re d DM 1 ' 2 ' 3 ' ^ I M 1 P 2 P 1 T 2 DW HTW .1__ LI I I « Age Prod. In t. Dept No. P la n t Ho. P r e lim . O p era tio n Code Occupat io n Cod e P erio d Ending Name o f Employee Remarks Expos. Hours WORKSHEET 1 . ____ .L - Date L e f t .L . I I R A C lock No. Date P la n t No. SPB Dept. No. B P relim . oper uoae OPE TH O peration D e s c r ip tio n Sex Model No. P ie c e Rate Dates T o ta ls STU Age i r /7TV>4f t* i ... \ B[TW - ________ | T o t a ls T o t a ls Remarks! T o t a l U nits W orksheet 2 T o t a l PW Earnings Avg,■ Pc. rlate P(•r Unit Instructions for Worksheets Worksheet 1 Section A # Clock Number — Record clock number listed on the worker's time card# If this number differs from the number on the personnel records, note this in "Remarks'' space# Plant — Record plant code from questionnaire# Dept# No#— Record department number as listed by the plant# Tf plant does not number departments use arbitrary code, and record code on plant questionnaire# Name of Employee — Record first and last name. Production Interval — Using the following code record time period for which production is measured# 1# - Week 2. - Two weeks 3# - Month Sex -- Indicate by 1 or 2 whether male or female# Date B o m — birth# Record number of month and last two digits of year of Age — Do not fill in at plant unless convenient as a means of selecting sample# IS) AS) “ Do not fill in at plant# ) PS) PPS — Prelim# Prod# Sample - Check liminary productivity sample of all piece-rate workers of same operations including at one worker under U5 years of to fulfill this condition do information# if workers belong to a pregroup. Such a group consists the same sex performing the least one worker over U5 and age* For groups which fail not take down productivity Preliminary Operation Code — Where available, record operation number (s) as used by establishment# Otherwise, leave blank# Occupation Code — Do not fill in at plant# 68 Occupation Description — From company personnel or pro duction records list worke r' s occupation during the period studied* Describe the occupation briefly in terns of specific operations performed. For persons whose produc tivity is to be compared, confirm from the appropriate plant official that all workers in an occupation actually perform the same operations. Also ascertain who is not a fully qualified operator, such as a beginner, or a recently transferred employee. P or T — Piece or Time Work - Indicate by "ln if worker is paid by piece rate and "2" if worker is paid on a time basis (hourly rate). If a worker is on both piecework and timework during the reporting period, indicate by nlw (i.e., list as piece rate worker). Hourly Rate — Record hourly wage rate for all timeworkers for whom personnel information is collected. In the case of piecerate workers, if average hourly piece rate earnings for the U busiest weeks of the year have already been computed by the company (as in the clothing industry), record in this cell. Otherwise, leave blank for piece rate workers. C. P« Date — Current Payroll- Record the month and day of the pay period nearest to the time of the plant visit, if the em ployee was on the payroll. If the employee was not on the pay roll, leave blank. H or M — Hand or Machine - Indicate by nl" or n2n whether worker Ts primarily a hand or a powered machine operator. QS — Section 6* Do not fill in at plant. For the reporting period on productivity, select, with the aid of the appropriate company official, a full production period totalling 8 weeks, preferably duri ng the first half of 1955, (not necessarily consecutive). If this is not available,use a minimum of U weeks for the period studied. Period Ending — Record number of the month and day and only the last digit of the year for the ending dates of the relevant period. If productivity information (second coltmn through fourth) is available on the basis of a 2-week pay period record productivity information in every other row; if it is monthly record on every fourth row. SPE — Refers to straight time piece work earnings. dollars and cents with .00 if no cents. - 69 - Include OPE — Refers to overtime piece work earnings. Do not adjust to straight time levels. Where records have overtime earnings already adjusted to straight time rates, indicate in "Remarks" space. Record both dollars and cents. TH — Refers to the total m m b e r of hours worked dinring the time period studied. HTW — Hours on Time Work - Refers to the total number of hours t o r which the worker was paid on a time basis (hourly rate) during the period studied. W and R — In plants which have, for individual workers, measures of the quality of output indicate in the appropriate column the number of quality warnings (W) received and the number of rejects (R) charged to the worker. If another f o m of quality measure is kept by the plant indicate in *Remarks" space, and if the infor mation is quantitative, record it in the W and R columns adjusting the titles. Absenteeism — The remaining columns in section B relate to absenteeism. Using the same 8-week full production period as used for productivity, record the weekday missed in the appropri ate cell. In most cases,these data will have to be obtained from individual employee timecard. In addition to the 8-week full produetion period, select, with the aid of the appropriate company official, four other weeks (not necessarily consecutive) in which the plant was on a less than full production schedule. M, T, W, Th, F — Refer to the specific weekday missed by the worker during the specified period. Record the code number of the day of the week the worker did not punch in. Note any day for which there is no entry on the timecard. If an individual punched in on Saturday of any week, note this information in the "Remarks" space with the appropriate ending date of the period. LM — Refers to the number of days the employee worked or was present during the specified period. DM ) ) Do not fill in at the plant. DWS) Date Hired — Record original date hired and subsequent dates rehired from beginning of absentee period to time of plant visit. Include day, month, and year if available. 70 Date Left — Record all dates left (by day, month, and year), from beginning of absenteeism period to time of plant visit. R — Refers to reason the worker left. Try to obtain reason for each incident and indicate by the following coding: Layoff Quit Discharge Years Service — Section C . -l -2 -3 Retired Other - k - 5 Do not fill in at plant* Record onljr work-connected injuries* Data should be obtained from workmen's compensation records, if possible* If these records are not available either at the plant or at an insurance company consult the records of the plant's first-aid station* If possible, data on injuries and exposure hours should be obtained for a maximum period of 2 years beginning 27 months prior to the date of the plant visit* Enter beginning and ending dates of time period for which exposure hours are recorded in the first and last cells of the exposure hour space* Note: All dates should be recorded in numerical form, e.g.: 9-22-5* Do not write out the month, and record only the final digit of the year. Date Disabled — Record date of beginning of disability. as date of injury, enter "same." If same Date Returned -- Record first date worked following disablement. If there is more than one continuous period of disablement re sulting from a single injury, enter starting and ending dates for each such period under "Date Disabled", and "Date Returned"* No. Days Disabled — Section D * Leave blank. This section is arranged to accomodate various methods plants employ to record individual employee's hours worked for long periods. From appropriate plant records the data may be directly available in annual, quarterly, monthly, or weekly totals. If data are available in annual totals, record figures in first and second cells of the bottom row; in quarterly total, record figures in cells of bottom row; in monthly totals, record figures in adjacent six cells in each column leaving the bottom row blank; 71 in weekly totals, record figures in all cells with exception of those in bottom row. For additional entries of weekly totals, use another worksheet recording individual’s clock number, plant number, and department number as well. Worksheet No, 2 Section A of this worksheet should be used in place of worksheet 1 (Row B) for recording information on piece-rate earnings where individual production records are available on a daily basis rather than by pay period. Refer to instructions for Section B of worksheet 1, Section B is to be used in those plants where there is reason to believe that the product mix for individual workers performing the same operations varies considerably. Record in formation for one week of the U-week production period during which earnings data are collected. Operation Description and Model N o ,— Record specific operations performed and enter the model numbers assigned to each product worked upon. These numbers are usually available from production records or from individual piece tickets. Piece Rate and Standard Time — Where piece rates are available, record the rates corresponding to the operations and models. In addition to piece rates, record time standards, if available, for all jobs for which product mix data are obtained. Time standards may be expressed, for instance, as standard minutes per unit or standard units per minute. Enter time standards in column headed STB, and enter definition of time standards in remarks space. Quantity Produced — For corresponding model numbers record the number of units produced during the production time period. Indicate the unit of measure in the cap after the word "unit,'* If unit of measure is not uniform throughout the worksheet, record units of measure in "Remarks," Dates refer to one day. Total Units ) ) Record only if directly available. Total FW ) at the plant. Earnings ) Average Piece Rate — Do not compute Do not fill in during plant visit# 72 ☆ U. S. GOVERNMENT PRINTING OFFICE : 1956 O - 403068